US11923725B2 - Transformerless multi-level medium-voltage uninterruptable power supply systems and methods - Google Patents
Transformerless multi-level medium-voltage uninterruptable power supply systems and methods Download PDFInfo
- Publication number
- US11923725B2 US11923725B2 US18/078,401 US202218078401A US11923725B2 US 11923725 B2 US11923725 B2 US 11923725B2 US 202218078401 A US202218078401 A US 202218078401A US 11923725 B2 US11923725 B2 US 11923725B2
- Authority
- US
- United States
- Prior art keywords
- voltage
- converter
- stage
- energy storage
- ups
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000003990 capacitor Substances 0.000 claims abstract description 105
- 238000004146 energy storage Methods 0.000 claims abstract description 86
- 238000001914 filtration Methods 0.000 claims description 3
- 230000002457 bidirectional effect Effects 0.000 abstract description 19
- 230000007935 neutral effect Effects 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 21
- 238000013528 artificial neural network Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 230000006698 induction Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- -1 e.g. Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001012 protector Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
Definitions
- the present disclosure generally relates to uninterruptible power supplies. More particularly, the present disclosure relates to compact uninterruptible power supplies that use a multi-level two stage dc-dc converter and a multi-level inverter to supply power from an energy storage device.
- the cost of copper has increased approximately 400% (from about $0.77/lb to about $4/lb).
- medium voltage (6.6 kV or 13.8 kV) distribution it is possible to reduce the size of the copper power supply cables, thereby reducing the cost of the power supply cables. It is also possible to reduce the critical power losses between the utility grid and the server computer rack by under 5% by using a transformerless medium voltage (MV) UPS and using a MV distribution system.
- MV transformerless medium voltage
- the DC-DC converter for the energy storage device of a UPS may use a single power semiconductor device to step up the voltage provided by the energy storage device, e.g., a battery, in the UPS.
- a single power semiconductor device is not available to step up the output voltage of the UPS so that it can connect across medium-voltage lines, for example, 6.6 kV or 13.8 kV AC lines. Therefore, the AC output of UPSs typically uses a step up transformer to step up a voltage of a battery.
- the transformer may step up the voltage of a battery at 700 V DC or some other low voltage to the AC voltage of the power supplied by the utility supply, for example, 13.8 kV or some other medium voltage.
- FIG. 1 shows a system 100 for supplying power to information technology (IT) and/or mechanical load 155 according to the prior art.
- the system 100 includes a utility/generator power supply system 195 and a UPS 115 that includes a step-up transformer 140 .
- power is supplied to the load 155 entirely by the utility supply 165 .
- the utility supply 165 supplies an AC voltage ranging from about 3.3 kV to about 13.8 kV.
- the mechanical portion of the load 155 includes electrical power required to operate cooling equipment required to remove waste heat generated by the IT portion of the load 155 .
- a surge protector 180 is used to limit voltage spikes in the power supplied by the utility supply 165 .
- a bypass line 162 allows maintenance tasks or other work to be performed on system 171 - 173 when ON/OFF switch of bypass line 162 (not shown) is closed and a static transfer switch (STS) 175 is opened.
- Line filters 170 are coupled to each AC line 171 , 172 , and 173 to reduce harmonics in the power supplied by the generator 160 or the utility supply 165 .
- the STS 175 supplies power to a step-down transformer 150 when the STS 175 is closed.
- the step-down transformer 150 can convert the medium voltage supplied by the utility supply 165 , e.g., 13.8 kV, to a low voltage, e.g., 400 V. The low voltage is then supplied to the load 155 having an appropriate current level.
- the STS 175 opens and the UPS system 115 starts supplying about 100% of the power to the load 155 via the UPS's transformer 140 .
- the UPS system 115 can supply power to the load 155 for a short period, e.g., approximately five minutes, but generally the generator 160 starts generating power if the interruption is more than a few seconds.
- the UPS system 115 generates power from a low-voltage energy storage device 105 , e.g., one or more low density lead-acid batteries B.
- the low voltage VB of the energy storage device 105 can range from about 300 V to about 600 V.
- the low voltage is then converted to a high voltage, e.g., approximately 700 V, by a bidirectional DC-DC converter 110 .
- the bidirectional DC-DC converter 110 includes one stage for converting the low voltage DC to a high voltage DC.
- the high voltage DC is then converted to a low AC voltage, e.g., approximately 400 V, using a two-level inverter 120 .
- the AC voltage output from the two-level inverter 120 passes through filter 130 , such as an inductor-capacitor (LC) filter, to a step-up transformer 140 .
- the step-up transformer 140 converts the low AC voltage to a medium AC voltage, e.g., about 13.8 kV.
- the medium AC voltage output from the step-up transformer 140 is then provided to the step-down transformer 150 , which converts the medium AC voltage to a low AC voltage, e.g., about 400 V, that is appropriate for the load 155 .
- transfer switch 190 shifts the primary power source from the utility supply 165 to the generator 160 .
- the output voltage of the UPS system 115 is synchronized to be in phase with the output voltage of the generator 160 .
- STS 175 is closed, a soft transfer from the UPS system 115 to the generator 160 is executed until the load 155 is entirely powered by the generator 160 .
- the energy storage device 105 of the UPS system 115 is then recharged by the power generated by the generator 160 .
- the load 155 is shifted from the generator 160 to the UPS system 115 because the utility supply 165 may be out of phase with the generator 160 and the STS 175 shifts the primary power source to the utility supply 165 .
- the output voltage of the UPS system 115 is then synchronized to be in phase with the output voltage of the utility supply 165 .
- the load 155 is quickly transferred from the UPS system 115 to the utility supply 165 .
- the energy storage devices 105 e.g., batteries B, of the UPS system 115 are recharged from the utility supply 165 so that the UPS system 115 is ready for future interruptions or disturbances in the utility supply 165 .
- the step-up transformer 140 in the UPS system 115 meets the power requirements of the load 155 ; however, the step-up transformer 140 is a large and bulky component of the UPS system 115 .
- the power density of the UPS system 115 is lower because the transformer 140 occupies a large amount of floor space, which, in some cities, can be quite expensive.
- the transformer 140 also introduces considerable losses (approximately 1 to 1.5% of the power) into the system thereby reducing the efficiency of the UPS system 115 .
- PWM pulse width modulation
- LC filters 130 which are expensive and bulky, are placed at the output of the two-level inverters 120 to reduce the current distortion or harmonics as demanded by the IT and/or mechanical load 155 .
- the systems and methods of the present disclosure provide power to a load using a medium voltage uninterruptible power supply (UPS) without using an output transformer.
- the UPS includes a DC-DC converter and an inverter.
- the DC-DC converter may be a two-stage multi-level DC-DC converter that may be configured for unidirectional or bidirectional power flow.
- the DC-DC converter generates a high DC voltage from a low or medium voltage energy storage device such as a battery and/or ultra capacitor.
- the multi-level inverter converts the high DC voltage into a medium AC voltage (from about 3.3 kV to 35 kV, e.g., about 13.8 kV).
- the UPS may also include a small filter to remove any harmonics generated by the DC-DC converter and/or the multi-level inverter.
- the present disclosure relates to a transformerless uninterruptible power supply (UPS) for an electrical load.
- the UPS includes an energy storage device, a two-stage DC-DC converter, and a multi-level inverter outputting a medium AC voltage.
- a negative terminal of the energy storage device, a negative terminal of the two-stage DC-DC converter, and a negative terminal of the multi-level inverter are electrically coupled to a common negative bus.
- the medium AC voltage may be between about 3.3 kV and about 35 kV.
- the two-stage DC-DC converter may include a first stage that generates a first output DC voltage and a second stage that generates a second output DC voltage higher than the first output DC voltage.
- a positive terminal of the second stage of the DC-DC converter and a positive terminal of the multi-level inverter may be electrically coupled to a common positive bus.
- the first stage may include two levels and the second stage may include more than two levels.
- the second stage may include three levels or five levels.
- the two-stage DC-DC converter may include a plurality of switches that form the levels of the first and second stages and a plurality of capacitors coupled together in a flying capacitor topology having a common negative bus.
- the medium AC output may be a three-phase AC output
- the multi-level inverter may include three sets of switches, each of which corresponds to one of the three phases of the three-phase AC output, and each set of switches may be configured in a diode-clamped multi-level topology.
- the multi-level inverter may convert the second output DC voltage into a third output voltage that is an AC voltage smaller than the second output DC voltage.
- the multi-level inverter may include more than two levels.
- the transformerless uninterruptible power supply may further include a filter electrically coupled to the AC output of the multi-level inverter to remove harmonics from the AC output of the multi-level inverter.
- the filter may be an inductor-capacitor-inductor filter.
- the transformerless uninterruptible power supply may further include a DC-DC converter controller and a multi-level inverter controller.
- the DC-DC converter controller controls the first stage with pulse width modulation control signals and controls the second stage in flying mode configuration with fixed duty cycle control signals.
- the multi-level inverter controller controls the multi-level inverter using space vector PWM control signals so as to perform neutral point voltage balancing.
- the two-stage DC-DC converter may be a bidirectional converter that allows the flow of power in a first direction from the energy storage device to the AC output of the multi-level inverter and in a second direction from the AC output of the multi-level inverter to the energy storage device.
- the two-stage DC-DC converter may be a unidirectional converter.
- the energy storage device may be a low voltage energy storage device.
- the low voltage may be between about 700 V and about 1200 V.
- the energy storage device may be a battery, an ultra-capacitor, or a battery and an ultra-capacitor electrically coupled to one another.
- the present disclosure features a transformerless uninterruptible power supply for an electrical load including an energy storage device, a single stage DC-DC converter, and a multi-level inverter having a medium AC voltage output.
- a negative terminal of the energy storage device, a negative terminal of the single stage DC-DC converter, and a negative terminal of the multi-level inverter are electrically coupled to a common negative bus.
- the single stage DC-DC converter may include a plurality of switches that form the levels of the single stage DC-DC converter and a plurality of capacitors coupled together in a flying capacitor topology having a common negative bus.
- the energy storage device may be a high voltage energy storage device.
- the high voltage may be between about 4 kV and about 7 kV.
- the energy storage device is a battery, an ultra-capacitor, or a battery and an ultra-capacitor electrically coupled to one another.
- the present disclosure features a method for supplying power from a transformerless uninterruptible power supply to an electrical load when an interruption in power occurs.
- the method includes supplying a first DC voltage from an low voltage energy storage device to a DC-DC converter, converting the first DC voltage into a second DC voltage, providing the second DC voltage to a multi-level inverter, and generating an AC voltage from the second DC voltage.
- the AC voltage is a medium voltage less than the second DC voltage.
- FIG. 1 is a schematic block diagram of a power supply system according to the prior art
- FIG. 2 is a schematic block diagram of a power supply system including a multi-level uninterruptible power supply (UPS) without any output transformer according to embodiments of the present disclosure;
- UPS multi-level uninterruptible power supply
- FIG. 3 is a circuit diagram of an embodiment of the multi-level two-stage unidirectional DC-DC converter section of the UPS of FIG. 2 ;
- FIG. 4 is a circuit diagram of another embodiment of the multi-level two-stage bidirectional DC-DC converter section of the UPS of FIG. 2 ;
- FIG. 5 is a circuit diagram of yet another embodiment of the multi-level single-stage bi-directional DC-DC converter section of the UPS of FIG. 2 ;
- FIG. 6 is a circuit diagram of still another embodiment of the multi-level two-stage bidirectional DC-DC converter of the UPS of FIG. 2 ;
- FIG. 7 is a circuit diagram of an embodiment of a five-level diode-clamped inverter of the UPS of FIG. 2 ;
- FIG. 8 is a space-vector modulation diagram showing switching states for Sector A of the 5-level inverter of FIG. 7 ;
- FIG. 9 shows the sequence of switching states and waveform of phase U for region 1 in Sector A(U A1 ) of the space-vector modulation diagram of FIG. 8 ;
- FIG. 10 is a circuit diagram of another embodiment of a six-level diode-clamped inverter of the UPS of FIG. 2 ;
- FIG. 11 is a circuit diagram of the multi-level two-stage bidirectional DC-DC converter of FIG. 4 coupled to the five-level diode-clamped inverter of FIG. 7 ;
- FIG. 12 is a schematic diagram of an embodiment of a filter of the UPS of FIG. 2 ;
- FIG. 13 is a flow diagram of a method for supplying power to a load when an interruption in utility power occurs according to embodiments of the present disclosure.
- the present disclosure relates to a multi-level, transformer-less, off-line energy storage UPS system that includes a multi-level DC-DC converter and a multi-level inverter coupled together.
- An on-line UPS is a double conversion UPS that it is connected in series with a power source.
- the efficiency of a conventional on-line UPS is about 93-96% because of the double-conversion losses (i.e., losses from the AC-DC converter and DC-AC inverter sections) and because of the series connection of the UPS with the power source.
- An off-line energy storage UPS in energy storage mode is connected in parallel with the power source.
- the efficiency of a conventional off-line UPS using an output transformer is about 97% to 98%.
- the transformer-less, off-line energy storage multi-level UPS according to the present disclosure can achieve efficiencies of about 98.5% to 99%.
- FIG. 2 is a schematic diagram of a system 200 for supplying power to the load 155 .
- the system 200 includes a transformer-less medium-voltage uninterruptible power supply (UPS) system 210 and a utility/generator power supply system 195 .
- An energy storage device 205 supplies power to a DC-DC converter 220 , as described in more detail below with respect to FIG. 3 , or a DC-DC converter 230 , as described in more detail below with respect to FIG. 4 .
- the energy storage device 205 designated as Vs, may be, for example, one or more high density Li-ion batteries and/or one or more ultra-capacitors where the battery and the ultra-capacitor are in parallel electrical connection with one another.
- the energy storage device 205 may supply between about 500 V and about 2000 V, and preferably between about 700 V and about 1200 V.
- the DC-DC converter 220 converts the DC voltage from the energy storage device 205 into a high DC voltage.
- the high DC voltage designated V 2 in FIGS. 3 and 4 , may be between about 18 kV and about 30 kV.
- the high DC voltage V 2 is converted into a medium AC voltage (e.g., about 13.8 kV) using a multi-level inverter 240 .
- Medium voltage (MV) distribution is cost effective because it reduces copper conduction costs of the distribution cable.
- the medium AC voltage may then pass to the step-down transformer 150 of the data center to supply an appropriate IT load voltage.
- a small filter 250 for example, an inductor-capacitor-inductor (LCL) filter, may be used to remove the harmonics from the medium AC voltage before passing it to the step-down transformer 150 , which converts the medium AC voltage to a low AC voltage, e.g., approximately 400 V AC.
- LCL inductor-capacitor-inductor
- FIGS. 3 - 6 are circuit diagrams of different embodiments of DC-DC converters 220 , 230 , 232 , and 234 that may be used with UPS system 210 .
- FIG. 3 depicts DC-DC converter 220 , described above with respect to FIG. 2 , which is a unidirectional DC-DC converter with two stages 224 and 226 .
- the first DC-DC stage 224 converts the voltage from the energy storage device 205 into voltage V 1 .
- Voltage V 1 is a DC voltage higher than the voltage of the energy storage device 205 .
- the second DC-DC stage 226 converts the voltage V 1 into voltage V 2 , which is higher than voltage V 1 .
- the voltage boost from the first and second stages 224 , 226 can range from about 1:5 to about 1:10.
- the voltage boost of the DC-DC converter 220 can be adjusted by changing the size of the switches at each level, the number of stages, and/or the number of levels in each stage.
- the optimum boost voltage requirement is based on the given voltage of the energy storage device 205 and the required voltage output from the inverter 240 .
- the boost voltage ratio can be lower.
- For higher voltage outputs from the inverter 240 the boost voltage ratio can be higher.
- the efficiency of the DC-DC converter 220 is reduced when the boost ratio is greater than about 7.
- the first stage 224 of the DC-DC converter 220 is shown as a unidirectional, two-level DC-DC converter having one insulator gate bipolar transistor (IGBT) switch S 1 connected in series with one diode D 1 .
- the switch S 1 and the diode D 1 are connected to the energy storage device 205 through an LC filter, which includes capacitor C 1 and inductor L 1 .
- Capacitor C 1 is connected in parallel across the terminals of energy storage device 205 from junction 2241 on the negative terminal to junction 2242 on the positive terminal.
- Inductor L 1 is connected from the positive junction 2242 to the collector terminal of switch S 1 at junction 2243 .
- the switch S 1 is connected from the positive junction 2243 to junction 2244 on the negative terminal side of energy storage device 205 which is at an equipotential with junction 2241 .
- Anode terminal of Diode D 1 is connected from the positive junction 2243 to positive junction 2245 .
- Capacitor C 2 is connected from positive junction 2245 to negative junction 2246 with is at an equipotential with junctions 2241 and 2244 .
- Voltage V 1 is the potential difference between junction 2245 and junction 2246 across capacitor C 2 .
- diode D 1 and capacitor C 2 are connected in series with respect to the energy storage device 205 .
- the first stage 224 may provide a range of duty or boost ratios.
- the boost ratio may range from 0 to 0.9.
- the output voltage (V 1 ) ranges from 1 kV to 10 kV depending on the value of the boost ratio, as shown in Table 1.
- the voltage V 1 varies depending upon the inductance of L 1 multiplied by the rate of current change di/dt.
- voltage V 1 refers to the voltage output of the first stage of a DC-DC converter.
- voltage V 2 refers to the output voltage of the final stage of a DC-DC converter.
- the IGBT in switch S 1 may be configured in such a way as to handle a lower voltage and a higher current. Furthermore, because the IGBT of switch S 1 is handling a lower voltage, the overall size of the IGBT may be smaller.
- Output capacitor C 2 and inductor L 2 connect the first stage 224 to the second stage 226 . More particularly, inductor L 2 is connected from the positive junction 2245 to a positive junction 2260 which forms a common positive junction for the second stage 226 .
- the second stage 226 depicts a five-level, unidirectional DC-DC converter; however, as illustrated in FIGS. 4 - 6 , both the first and second stages 224 , 226 may include different numbers of levels than are illustrated in FIG. 3 .
- four switches S 20 -S 23 and four diodes D 20 -D 23 are shown connected together with capacitors C 3 -C 12 in a multi-level flying capacitor unidirectional arrangement. More particularly, diode D 23 is connected from positive junction 2260 to positive junction 2261 . Capacitor C 3 is connected from positive junction 2261 to negative junction 2271 which is on the emitter side of switch S 20 . The collector side of switch S 20 is connected from positive junction 2260 . Voltage V 21 is measured across capacitor C 3 from positive junction 2261 to negative junction 2271 .
- diode D 22 is connected from positive junction 2261 to positive junction 2262 .
- Capacitors C 4 and C 5 are connected in series from positive junction 2262 to negative junction 2272 at the emitter side of switch S 21 .
- the collector side of switch S 21 is connected to negative junction 2271 .
- Voltage V 22 is measured across capacitors C 4 and C 5 from positive junction 2262 to negative junction 2272 .
- diode D 21 is connected from positive junction 2262 to positive junction 2263 .
- Capacitors C 6 , C 7 , and C 8 are connected in series from positive junction 2263 to negative junction 2273 at the emitter side of switch S 22 .
- the collector side of switch S 22 is connected to negative junction 2272 .
- Voltage V 23 is measured across capacitors C 6 , C 7 , and C 8 from positive junction 2263 to negative junction 2273 .
- diode D 20 and capacitors C 9 , C 10 , C 11 , and C 12 are each connected in series from positive junction 2264 to negative junction 2274 on the emitter side of switch S 23 .
- the collector side of switch S 23 is connected to negative junction 2273 .
- the emitter side of S 23 is connected to negative junction 2274 , which is at an equipotential with negative junctions 2241 , 2244 , and 2246 .
- Voltage V 2 is measured across capacitors C 9 , C 10 , C 11 , and C 12 from positive junction 2264 on the output (cathode) side of diode D 20 to negative junction 2274 at the negative side of capacitor C 12 .
- Negative junction 2274 is at an equipotential with negative junctions 2246 , 2244 , and 2241 .
- Each switch S 20 -S 23 in the second stage 226 is rated same as voltage of switch S 1 in the first stage 224 but its rated current capacity is lower to handle smaller current in the second stage 226 .
- the capacitors C 3 -C 12 are relatively small capacitors, e.g., capacitors rated for about 5 kV with a capacitance value that is about ten times less than a capacitor for a conventional DC-DC converter. For example, if a conventional two-level DC-DC converter needs a capacitor having a value of about 2000 ⁇ F, then the multi-level flying capacitor arrangement (i.e., C 3 -C 12 ) needs a capacitor having a value of about 200 ⁇ F. In a five-level arrangement, each switch S 20 -S 23 operates at a fixed duty cycle of 25% and a fixed switching frequency without pulse width modulation.
- the voltages V 21 , V 22 , V 23 , and V 2 across the capacitors C 3 -C 12 may be balanced in every switching cycle due to fixed duty cycle operation. Additionally, the voltage across each switch S 20 -S 23 maintains 25% of the high voltage V 2 .
- the voltage V 21 across C 3 is equal to 1 ⁇ V 1 of C 2 ; the voltage V 22 across capacitors C 4 and C 5 is equal to 2 ⁇ V 1 ; the voltage V 23 across capacitors C 6 -C 8 is equal to 3 ⁇ V 1 ; and the voltage across C 9 -C 12 , which is voltage V 2 , is equal to 4 ⁇ V 1 .
- the voltage across C 2 is V 1 . Since the junction 2271 is at the same potential as junctions 2246 and 2274 due to switching on the switches S 21 , S 22 , and S 23 , and switching off the switch S 20 , the voltage V 21 across C 3 is equal to V 1 . As a result, the boost ratio of the second stage 226 is 1:4.
- the use of the diodes D 1 and D 20 -D 23 allow for current to flow in one direction in the unidirectional DC-DC converter 220 .
- an additional charger (not shown) is required to charge the energy storage device 205 when the generator 160 or the utility supply 165 is supplying power to the load 155 .
- FIG. 4 shows another embodiment of the DC-DC converter 220 of FIG. 2 , which is a two-stage, bidirectional DC-DC converter 230 .
- the two-stage bidirectional DC-DC converter 230 can be used to supply power from the energy storage device 205 to the load 155 when power from the generator 160 or utility supply 165 is interrupted or to charge the energy storage device 205 with power from the generator 160 or the utility supply 165 when the generator 160 or the utility supply 165 is supplying power to the load 155 .
- the two-stage bidirectional DC-DC converter 230 is a bi-directional version of the two-stage unidirectional DC-DC converter 220 of FIG. 3 .
- diode D 1 is now replaced in first stage 224 ′ by switch S 2 and in second stage 226
- diodes D 20 , D 21 , D 22 , and D 23 are now replaced in second stage 226 ′ by switches S 24 , S 25 , S 26 , and S 27 , respectively.
- Switches S 1 and S 20 -S 23 are used to supply power to the load 155 and switches S 2 and S 24 -S 27 are used to charge the energy storage device 205 .
- switch S 1 is configured as a boost converter that converts the voltage Vs of the energy storage device 205 to a higher voltage and the switch S 2 is configured as a buck converter that converts voltage from the generator 160 or utility supply 165 to a lower voltage appropriate for charging the energy storage device 205 , e.g., a voltage slightly more than Vs.
- Voltage V 201 is measured across switches S 20 and S 27 and capacitor C 3 from junction 2261 to junction 2271 .
- Voltage V 202 is measured across switches S 21 and S 26 and capacitors C 4 and C 5 from junction 2262 to junction 2272 .
- Voltage V 203 is measured across switches S 22 and S 25 and capacitors C 6 , C 7 , and C 8 from junction 2263 to junction 2273 .
- Voltage V 2 is then measured across switches S 23 and S 24 and capacitors C 9 , C 10 , C 11 , and C 12 from junction 2264 to junction 2274 .
- Each of the switches S 20 -S 27 outputs a voltage equal to the input voltage V 1 .
- the capacitance of capacitor C 9 equals the capacitance of capacitor C 2
- the capacitance of capacitor C 10 equals the capacitance of capacitor C 2
- the capacitance of capacitor C 11 equals the capacitance of capacitor C 2
- the capacitance of capacitor C 12 equals the capacitance of capacitor C 2 .
- the switches S 20 -S 27 are connected in series, the output voltage V 2 is equal to the sum of the voltages output from each of the switches S 20 -S 27 .
- the boost ratio is 4:1 and V 2 equals 4 ⁇ V 1 .
- FIG. 5 shows yet another embodiment of the DC-DC converter 220 of FIG. 2 , which is a one-stage 228 , bidirectional DC-DC converter 232 .
- the one-stage 228 of DC-DC converter 232 includes the energy storage device 205 , capacitor C 1 , and inductor L 1 configured in the same manner as first stage 224 in FIG. 4 .
- switches S 1 and S 2 , capacitor C 2 and inductor L 2 are now omitted.
- the bi-directional DC-DC converter 232 includes six levels, i.e., five switches S 60 -S 64 on a top side and five switches S 65 -S 69 on a bottom side, to convert the DC voltage Vs from the energy storage device 205 into the DC voltage V 2 . Since switches S 1 and S 2 , capacitor C 2 , and inductor L 2 , i.e., the first stage, are omitted, there is no voltage V 1 .
- Voltage V 211 is measured across switches S 64 and S 65 and capacitor C 20 from junction 2281 to junction 2291 .
- Voltage V 212 is measured across switches S 32 and S 66 and capacitors C 21 and C 22 from junction 2282 to junction 2292 .
- Voltage V 213 is measured across switches S 62 and S 67 and capacitors C 23 , C 24 , and C 25 from junction 2283 to junction 2293 .
- Voltage V 214 is measured across switches S 61 and S 68 and capacitors C 26 , C 27 , C 28 , and C 29 from junction 2284 to junction 2294 .
- Voltage V 2 is then measured across switches S 60 and S 69 and capacitors C 30 , C 31 , C 32 , C 33 , and C 34 from junction 2285 to junction 2295 .
- the DC voltage Vs is converted directly into the DC voltage V 2 without an intermediate voltage V 1 .
- the boost ratio is about 1:18 to about 1:24 for lower energy storage voltages, e.g., 1 kV.
- the efficiency of a DC-DC converter is reduced when the high boost conversion ratio is greater than about 7.
- the boost ratio of each stage is about 1:4 to about 1:6.
- the voltage of the energy storage device is high (e.g., about 4 kV to about 6 kV), which reduces the boost conversion ratio to around 5 to 7. This improves the efficiency of the DC-DC converter 232 .
- FIG. 6 shows yet another embodiment of the DC-DC converter 220 of FIG. 2 or bi-directional DC-DC converter 230 of FIG. 4 .
- This embodiment is a two-stage bidirectional DC-DC converter 234 .
- the first stage 235 of DC-DC converter 234 includes three levels and the second stage also includes three levels.
- the voltage V 1 is greater than the voltage of the energy storage device 205 and the voltage V 2 is greater than the voltage V 1 .
- the first stage 235 includes capacitors C 40 -C 42 in a flying capacitor configuration.
- the second stage 236 includes capacitors C 43 -C 45 in a flying capacitor configuration.
- the first stage 235 uses three levels with each switch S 70 -S 73 operating at a fixed duty cycle of 50%.
- Switches S 70 -S 73 are arranged in a buck-boost configuration.
- the switches S 70 -S 73 supply an output voltage that is greater (when supplying power to the load 155 ) or less (when charging the energy storage device 205 ) than the input voltage.
- the switches S 70 -S 73 step up the voltage supplied by the energy storage device 205 to the load 155 , and step down the voltage provided by the generator 160 or the utility supply 165 to the energy storage device 205 to charge the energy storage device 205 . If the voltage of the energy storage device 205 is about 5 kV and the boost ratio is about 1:2 (at 50% duty ratio), then the output voltage V 1 is about 10 kV.
- each of the switches S 70 -S 73 may be standard converters, which are operated to output the same voltage that is input to the switches S 70 -S 73 .
- the battery voltages would need to be, for example, about 5 kV to obtain the desired voltage of 10 kV in a single stage. Therefore, both a high-voltage energy storage device (e.g., a 5 kV battery string) and a high-voltage IGBT switching device are needed for charging the energy storage device 205 to obtain a boost ratio of about 1:2 in a single stage and a boost ratio of about 1:4 in a two-stage configuration.
- the first stage includes five switches (i.e., six levels) on the upper half, each of which output the same voltage as the input voltage, then the five switches would provide a boost ratio of about 1:5.
- the second stage includes four switches (i.e., five levels) on the upper half, each of which output the same voltage as the input voltage, then the four switches would provide a boost ratio of about 1:4.
- the combination of the first and second stages would provide an overall boost ratio of about 1:20.
- the second stage 236 of FIG. 6 also uses three levels with each switch S 75 -S 78 operating at a fixed duty cycle of 50%.
- Each of switches S 75 -S 78 is a standard converter that outputs a voltage that is the same as the input voltage.
- the boost ratio is about 1:2, which results in an overall boost ratio of about 1:4 in a two-stage configuration.
- FIGS. 3 - 6 show one- or two-stage DC-DC converters. Other embodiments may include more than two stages.
- the number of capacitors coupled in series between the collectors of switches arranged in the upper portion of a stage and the emitters of the switches arranged in the lower portion of the stage depends on the level of the switch to which the capacitors are coupled.
- capacitors C 9 -C 12 FIG. 4
- the DC-DC converters 220 , 230 , 232 , or 234 may include any number of capacitors coupled in series between the collectors and emitters of appropriate switches to achieve a desired result.
- the DC-DC converter 220 of FIG. 3 and the DC-DC converter 230 of FIG. 4 are five-level converters in flying capacitor configuration.
- FIGS. 7 and 10 show inverters 240 or 810 , respectively, which may be used to convert the DC voltage output V 2 from the converters 220 , 230 , 232 , or 234 to 3-phase AC voltage V 3 .
- FIG. 7 shows a five-level diode-clamped inverter 240 .
- the five-level inverter 240 includes three groupings of switches and diodes 242 , 244 , and 246 to generate the three phases V 3 a , V 3 b , and V 3 c of the AC voltage V 3 , which is the output voltage of the inverter 240 .
- Each grouping of diodes D 30 -D 35 , D 40 -D 45 , and D 50 -D 55 and corresponding switches S 30 -S 37 , S 40 -S 47 , and S 50 -S 57 are connected together in a diode-clamped configuration.
- Switches S 30 -S 37 , S 40 -S 47 , and S 50 -S 57 may be IGBTs. IGBTs allow for higher currents and higher switching frequencies.
- the five-level inverter 240 illustrated in FIG. 7 allows for sharing of the high voltage among the switches S 30 -S 37 , S 40 -S 47 , and S 50 -S 57 and reduces harmonic distortion.
- the harmonics of voltage V 3 may be so low (e.g., less than about 5 percent) that a filter (e.g., filter 130 ) may not be needed on the voltage V 3 output line.
- the inverter 240 of FIG. 2 may be a four-level or higher inverter.
- the switches S 30 -S 37 , S 40 -S 47 , and S 50 -S 57 are controlled by a microprocessor (not shown) such as a digital signal processor (DSP) (not shown).
- the DSP may use a space vector pulse width modulation (SVPWM) technique for operating the switches S 30 -S 37 , S 40 -S 47 , and S 50 -S 57 in such a way that the neutral-point voltage remains balanced in open-loop operation.
- the SVPWM technique is an inverter modulation technique for synthesizing a voltage space vector V* (described below with respect to FIG. 8 ) over a modulation sampling period T s (see FIG. 9 discussed below).
- the SVPWM technique provides the advantages of superior harmonic quality and large under-modulation range that extends the modulation factor from 78.5% to 90.7%.
- an artificial neural network ANN can be used to reduce harmonics outputted from the inverter 240 or 810 and can eliminate the need for the filter 250 (see FIG. 2 ) on the output lines having voltage V 3 (see FIGS. 7 and 10 ).
- space vector pulse width modulation of three-level inverters is described in “Space Vector Pulse Width Modulation of Three-Level Inverter Extending Operation Into Overmodulation Region,” by Subrata K. Mondal, Bimal K. Bose, Valentin Oleschuk and Joao O. P. Pinto, published in IEEE Transactions on Power Electronics, Vol. 18, No. 2, March 2003, 0885-8993 ⁇ 2003 IEEE, the entire contents of which is hereby incorporated by reference herein.
- FIG. 8 is a space-vector modulation diagram 300 showing switching states for Sector A of the 5-level inverter 240 of FIG. 7 according to embodiments of the present disclosure.
- FIG. 9 shows the sequence of switching states of phase U for region 1 in Sector A (U A1 ) of the space-vector modulation diagram 300 in FIG. 8 .
- the switching states for the space-vector modulation diagram 300 are such that the sequence of switching causes balancing of the voltages across the capacitors C 13 , C 14 , C 15 and C 16 of the 5-level inverter 240 of FIG. 7 in open loop operation.
- space-vector modulation diagram 300 is formed by a hexagon 302 .
- the number of switching states is determined by raising the number of levels, e.g., 5, to the power of the number of phases, e.g., 3 for phases U, V, and W. Therefore, the number of switching states is 125 (5 3 ). Since there are six sectors, i.e., Sectors A, B, C, D, E, and F, with 20 active states per sector, the total number of active states is 120 (6 ⁇ 20). The active states are those states extending beyond the center point V 0 .
- the SVPWM technique is an inverter modulation technique for synthesizing a voltage space vector V*.
- voltage space vector V* originates at the center point V 0 .
- the voltage space vector V* is characterized by a constant voltage value represented by a first circle 310 so that the voltage space vector V* may rotate around the center point V 0 . Therefore, all switching states at the circumference of the first circle 310 are at the same voltage V*.
- the voltage space vector V* is characterized by a constant voltage value represented by a second circle 312 that is concentric with first circle 310 , the voltage space vector V* then assumes a constant voltage represented by the second circle 312 .
- the constant voltage represented by the second circle 312 is greater than the constant voltage represented by the first circle 310 .
- the constant voltage represented by the second circle 312 would be less than the constant voltage represented by the first circle 310 .
- Table 2 below illustrates the switching states for switches SX 0 -SX 7 of the inverter 240 , where X is 3, 4, or 5. Operation of each set of switches SX 0 -SX 7 of FIG. 7 produces a phase of the three-phase AC output.
- the closing of a switch is represented by the numeral “1” and the opening of a switch is represented by the numeral “0.”
- junction 2400 represents state O, so that state represents neutral point balancing so that the average current injected at O should be zero.
- Voltage V 2 is measured at junction 2400 located between capacitors C 14 and C 15 .
- States P 1 and P 2 represent positive bus voltage.
- States N 1 and N 2 represent negative bus voltages.
- State P 1 is represented by a voltage at junction 2401 between capacitors C 14 and C 13 .
- State P 2 corresponds to a voltage at junction 2413 on common positive bus 2411 that electrically couples junction 2400 , capacitor C 14 , junction 2401 , and capacitor C 13 to junction 2420 for phase V 3 a or U.
- Switches S 30 , S 31 , S 32 , and S 33 are electrically coupled to common positive bus 2411 at junction 2402 via the collector side of switch S 30 .
- state N 1 corresponds to a voltage at junction 2401 ′ between capacitors C 15 and C 16 .
- State N 2 corresponds to a voltage at junction 2414 on common negative bus 2412 that electrically couples junction 2400 , capacitor C 15 , junction 2401 ′ and capacitor C 16 to junction 2420 for phase V 3 a or U.
- Switches S 34 , S 35 , S 36 , and S 37 are electrically coupled to common negative bus 2412 at junction 2402 ′ via the emitter side of switch S 37 .
- phase W (V 3 c in FIG. 7 ), for example, is in state P 2 (positive bus voltage) when the switches S 30 , S 31 , S 32 , and S 33 are closed or ON and switches S 34 , S 35 , S 36 , and S 37 are open or OFF
- the phase W is in state P 1 (positive bus voltage that is less than P 2 ) when switches S 30 , S 35 , S 36 , and S 37 are open or OFF and switches S 31 , S 32 , S 33 , and S 34 are closed or ON.
- the phase W is in state O when switches S 30 , S 31 , S 36 , and S 37 are open or OFF and switches S 32 , S 33 , S 34 , and S 35 are closed or ON.
- the phase W is in state N 1 , which corresponds to a negative bus voltage that is greater than a negative bus voltage that corresponds to state N 2 , when switches S 30 , S 31 , S 32 , and S 37 are turned off (i.e., open) and switches S 33 , S 34 , S 35 , and S 36 are turned on (i.e., closed).
- the phase W is in state N 2 , which corresponds to a negative bus voltage that is less than the negative bus voltage that corresponds to state N 1 , when switches S 30 , S 31 , S 32 , and S 33 are turned off (i.e., open) and switches S 34 , S 35 , S 36 , and S 37 are turned on (i.e., closed).
- the states P 2 , P 1 , O, N 1 , and N 2 , and waveform 320 are plotted versus a sampling period Ts or symmetrically over half a sampling period Ts/2 for the phase U A in Sector A.
- the top portion of FIG. 9 also shows the switching states P 2 , P 1 , O, N 1 , and N 2 of all three phases UA, VA, and WA.
- the modulation strategy illustrated in FIGS. 7 , 8 , and 9 is a DSP-based SVPWM modulation strategy for a 5-level UPS system, e.g., the 5-level inverter 240 of FIG. 7 .
- FIG. 10 shows a six-level inverter 810 . Similar to FIG. 7 , the switches and diodes are connected into three groups 820 , 830 , 840 , with each group providing one phase of the AC voltage V 3 .
- the six-level inverter 810 includes five capacitors C 13 -C 17 .
- the diodes D 80 -D 87 , D 90 -D 97 , and D 800 -D 807 , and the switches S 80 -S 89 , S 90 -S 99 , and S 800 -S 809 are connected in a diode-clamped configuration. However, other configurations may be used.
- the neutral state O is measured at the junction between capacitors C 14 and C 15 .
- Voltage V 2 is measured from junction 851 on the collector side of switches S 80 -S 89 , S 90 -S 99 , and S 800 -S 809 to junction 852 on the emitter side of switches S 80 -S 89 , S 90 -S 99 .
- the locations of the P and N states in the six-level inverter 810 differ from the locations of P 2 , P 1 , N 1 and N 2 described above with respect to five level inverter 240 in FIG. 7 and are not described or shown herein.
- FIG. 11 shows the integration of the DC-DC converter 230 of FIG. 4 and the inverter 240 of FIG. 7 into a transformerless medium voltage multi-level uninterruptible power supply (PS) system 600 for the electrical load 155 in FIG. 2 .
- the transformerless medium voltage multi-level uninterruptible power supply (PS) system 600 is electrically coupled to a common DC power positive bus 901 via terminals 903 and 905 and to a common DC power negative bus 902 via terminals 904 , 906 and 908 .
- the capacitors C 9 -C 12 may be the same as capacitors C 13 -C 16 , respectively. In embodiments, any one of the converters 220 , 230 , 232 , or 234 of FIGS.
- the converter/inverter combination may include a converter with one or more stages and one or more levels per stage.
- the converter/inverter combination may also include an inverter with one or more levels, e.g., three levels with two switches in each phase grouping.
- the converter/inverter combination may include a filter 250 (see FIG. 2 ) coupled to each output line that supplies voltage V 3 .
- the transformerless uninterruptible power supply system 600 includes energy storage device 205 that provides DC output voltage Vs, two-stage DC-DC converter 230 having DC output voltage V 2 and multi-level inverter 240 having medium AC voltage output V 3 , wherein negative terminal 904 of the energy storage device 205 , negative terminal 906 of the two-stage DC-DC converter 230 , and negative terminal 908 of the multi-level inverter 240 are electrically coupled to a common negative bus/common negative potential 902 .
- the two-stage DC-DC converter 230 includes first stage 224 ′ that generates first output DC voltage V 1 and second stage 226 ′ that generates second output DC voltage V 2 that is higher than the first output DC voltage V 1 .
- Positive terminal 903 of the second stage 226 ′ of the DC-DC converter 230 and positive terminal 905 of the multi-level inverter 240 are electrically coupled to a common positive bus 901 .
- the first stage 224 ′ includes two levels, e.g., switches S 1 and S 2
- the second stage 226 ′ includes more than two levels, e.g., switches S 20 -S 27 which represent a five-level flying capacitor configuration.
- the second stage 226 ′ includes three levels (not shown).
- the two-stage DC-DC converter 230 includes the plurality of switches S 1 , S 2 , and S 20 -S 27 (which are divided into a first set 1011 and a second set 1012 ), which form the levels of the first stage 224 ′ and the second stage 226 ′, and a plurality of capacitors C 3 , C 4 , C 5 , C 6 , C 7 and C 8 coupled together in a flying capacitor topology.
- the plurality of switches S 1 , S 2 , and S 20 -S 27 , and the flying capacitor topology are electrically coupled to a common negative bus 902 .
- the multi-level inverter 240 converts the second output DC voltage V 2 into the third output voltage V 3 that is an AC voltage smaller than the second output DC voltage V 2 .
- a transformerless uninterruptible power supply 275 that includes the components identified above with respect to transformerless uninterruptible power supply 600 , includes filter 250 that is electrically coupled to the AC output of the multi-level inverter 240 and is configured to remove harmonics from the AC output of the multi-level inverter 240 occurring in voltage V 3 .
- the filter 250 may be an inductor-capacitor-inductor filter.
- the two-stage DC-DC converter 230 is a bidirectional converter that is configured to allow the flow of power in a first direction from the energy storage device 205 to the AC output of the multi-level inverter 240 and in a second direction from the AC output of the multi-level inverter 240 to the energy storage device 205 .
- the energy storage device 205 may be a low voltage energy storage device wherein the low voltage is between about 700 V and about 1200 V.
- the energy storage device 205 may be a battery, an ultra-capacitor, or a battery and an ultra-capacitor electrically coupled to one another.
- the transformerless uninterruptible power supply 600 may be configured with the unidirectional two-stage DC-DC converter 220 described above with respect to FIG. 3 .
- the multi-level inverter 240 includes more than two levels.
- the AC output is a three-phase AC output that includes phase V 3 a (or U), phase V 3 b (or V) and phase V 3 c (or W).
- the multi-level inverter includes three sets of switches, e.g., set 1013 that includes switches S 30 -S 37 that are clamped to set D 300 of diodes D 30 -D 37 , set 1014 that includes switches S 40 -S 47 that are clamped to set D 400 of diodes D 40 -D 47 and set 1015 that includes switches S 50 -S 57 that are clamped to set D 500 of diodes D 50 -D 57 .
- Each set of switches and diodes corresponds one of the three phases of the three-phase AC output, and each set of switches is configured in a diode-clamped multi-level topology. More particularly, set 1013 corresponds to phase V 3 c (or W), set 1014 corresponds to phase V 3 b (or V) and set 1015 corresponds to phase V 3 a (or U).
- the transformerless uninterruptible power supply 600 may be configured instead with the single stage DC-DC converter 232 of FIG. 5 (not shown).
- the energy storage device 205 and the multi-level inverter 240 again having medium AC voltage output V 3 , are included, wherein the negative terminal 904 of the energy storage device 205 , the negative terminal 906 of the single stage DC-DC converter 220 , and the negative terminal 908 of the multi-level inverter 240 are again electrically coupled to a common negative bus/common negative potential 902 .
- the single stage DC-DC converter 232 also includes the set of switches S 60 -S 69 that form the levels of the single stage DC-DC converter 232 and the plurality of capacitors C 20 -C 35 coupled together in a flying capacitor topology electrically coupled to the common negative bus 902 .
- the energy storage device 205 is a high voltage energy storage device wherein the high voltage is between about 4 kV and about 7 kV.
- the energy storage device 205 may be a battery, an ultra-capacitor, or a battery and an ultra-capacitor electrically coupled to one another.
- the transformerless uninterruptible power supply 600 may further include a DC-DC converter controller 1002 that is configured to control the first stage 224 ′ with pulse width modulation control signals A 1 to switch set 1011 and configured to control the second stage 226 ′ with fixed duty cycle control signals A 2 to switch set 1012 .
- the transformerless uninterruptible power supply 600 may further include a multi-level inverter controller 1004 that is configured to control the multi-level inverter 240 using space vector PWM control signals B 1 to switch set 1013 and diode set D 300 , control signals B 2 to switch set 1014 and diode set D 400 , and control signals B 3 to switch set 1015 and diode set D 500 so as to perform neutral point voltage balancing.
- a multi-level inverter controller 1004 that is configured to control the multi-level inverter 240 using space vector PWM control signals B 1 to switch set 1013 and diode set D 300 , control signals B 2 to switch set 1014 and diode set D 400 , and control signals B 3 to switch set 1015 and diode set D 500 so as to perform neutral point voltage balancing.
- FIG. 12 shows one type of filter 250 that may be connected to the output of the inverter 240 of FIG. 2 .
- Filter 250 is an LCL filter including two inductors L 3 and L 4 connected in series and a capacitor C 18 connected at one end “a” between the two inductors L 3 and L 4 and connected at the other end “b” to neutral.
- the filter 250 removes the undesirable harmonics from each output of the inverter 240 and supplies a filtered AC voltage to the load 155 via the step-down transformer 150 .
- FIG. 13 is a flow diagram of a process 1100 for supplying power to a load 155 using the UPS system 210 of FIG. 2 or the UPS 600 of FIG. 11 .
- the process 1100 starts at step 1105 when an interruption or disturbance is detected at step 1110 .
- a first DC voltage V 1 is generated from an energy storage device 205 using one or more buck-boost converters or one or more standard converters. If the energy storage device 205 supplies a voltage Vs between about 400V and about 1200 V, then the first voltage V 1 can be a medium voltage from about 666 V to about 2 kV (with a boost duty ratio of 0.4) when using one buck-boost converter.
- the first voltage V 1 is converted into a second DC voltage V 2 at step 1130 .
- the second voltage V 2 is a high DC voltage from about 8 kV to about 24 kV when using more than a three-level converter, for example, the five-level converter 220 or 230 shown in FIGS. 3 and 4 .
- the second voltage V 2 is converted into a third voltage V 3 that is an AC voltage by the inverter 240 .
- the third voltage V 3 is an AC voltage lower than the second voltage V 2 .
- the second voltage V 2 is the DC voltage shown in Table 3, e.g., 21 kV DC
- the UPS system 210 includes a five-level inverter 240
- the third voltage V 3 is the corresponding AC voltage shown in TABLE 3 on the same row, e.g., 13.8 kV AC.
- step 1150 the AC or third voltage V 3 output from the inverter 240 may pass through a filter, such as the LCL filter 250 shown in FIG. 12 , in step 1150 . Then, in step 1160 , the AC or third voltage V 3 is supplied to load 155 . After a certain period not exceeding a maximum battery discharge period, e.g., about five minutes, the supply of power from the UPS system 210 is transferred to the generator 160 or the utility supply 165 at step 1170 . The generator 160 or the utility supply 165 charges the energy storage device 105 using the bidirectional inverter 240 and converters 230 at step 1180 .
- a charging apparatus (not shown) must be added to the UPS to charge the energy storage device 105 .
- the process 1100 ends at step 1185 after the generator 160 or the utility supply 165 supplies power to the load 155 and the energy storage device 105 is recharged.
- the embodiments of the present disclosure include, for example, referring to FIG. 2 , uninterruptible power supply 200 for electrical load 155 that is electrically coupled to step-down transformer 150 .
- the step-down transformer 150 has a desired input voltage.
- the uninterruptible power supply 210 includes multi-level DC-DC converter 220 or 230 as illustrated in FIGS. 3 and 4 , respectively and multi-level inverter 240 having an AC voltage output V 3 (see FIG. 7 )
- the multi-level inverter 240 is electrically coupled to the multi-level DC-DC converter 220 or 230 .
- the AC voltage output V 3 of the multi-level inverter 240 is greater than or equal to the desired input voltage of the step-down transformer 150 when energy storage device 205 , Vs provides power to the multi-level DC-DC converter 220 or 230 .
- the multi-level DC-DC converter 220 or 230 includes first stage 224 or 224 ′ that generates first output DC voltage V 1 and second stage 226 or 226 ′ that generates second output DC voltage V 2 that is higher than the first output DC voltage V 1 .
- the AC voltage V 3 is a medium voltage and is generated without a step-up transformer for stepping up the voltage to a level greater than or equal to the desired input voltage of the step-down transformer 150 supplying power to the electrical load 155 .
- the uninterruptible power supply 200 includes energy storage device 205 , Vs that is configured to supply first DC voltage V 1 .
- Multi-level DC-DC converter 220 or 230 is coupled to the energy storage device 205 , Vs and is configured to transform the first DC voltage V 1 into second DC voltage V 2 that is greater than the first DC voltage V 1 , and multi-level inverter 240 that is coupled to the multi-level DC-DC converter 220 or 230 .
- the multi-level inverter 240 is configured to convert the second DC voltage V 2 into third voltage V 3 that is an AC voltage less than the second DC voltage V 2 .
- the UPS system 210 described above eliminates a bulky and expensive transformer that generates considerable losses. Indeed, the UPS system 210 may increase the efficiency of the UPS system 210 by about 0.5% because this transformer may produce energy losses of about 1%. Additionally, transformers are large in size and have a low power density. Therefore, by eliminating the transformer 140 , the UPS system 210 has a smaller footprint as well as a higher power density.
- the two-stage, bidirectional DC-DC converters described above e.g., bidirectional DC-DC converters 220 , 230 , 234 , provide higher system efficiency for higher boost ratio operation in comparison to single-stage DC-DC converters. For example, assuming that the energy storage device 105 has a nominal voltage of 1000 V, the boost ratio would be 1:21.
- the two-stage, bidirectional DC-DC converters also eliminate the need for an external battery charger.
- the two-stage, bidirectional DC-DC converters allow for the use of existing low voltage (e.g., 700 V to 1200 V) energy storage devices.
- the multi-level inverters 240 that are operated according to the SVPWM technique of the UPS system 210 provide better harmonic quality than the two-level inverters 120 that are operated according to a sinusoidal PWM technique. Thus, the requirements of the filters 250 are minimized or eliminated. If the total current harmonics of the inverter output are less than 1%, then there is no need for external filter.
- the multi-level inverters 240 may be controlled using space-vector PWM, which provides much better harmonic quality than sinusoidal PWM.
- the multi-level inverters 240 use a lower switching frequency, which results in lower voltage spikes. Therefore, the multi-level inverters 240 generate lower common mode voltages and the UPS system 210 needs lower EMI filtering in comparison to UPS systems using the two-level inverters 120 .
- the UPS system 210 of the present disclosure may be used across the full voltage spectrum of applications from low-voltage applications to very high voltage applications including medium voltage applications.
Abstract
Description
TABLE 1 | |||
VS (~1 kV) | Duty (Boost) | V1 | |
1 kV | 0 | 1 | |
1 kV | 0.2 | 1.25 | kV |
1 kV | 0.4 | 1.66 | kV |
1 kV | 0.6 | 2.5 | kV |
1 kV | 0.7 | 3.3 | kV |
1 kV | 0.8 | 5 | |
1 kV | 0.9 | 10 | kV |
TABLE 2 |
(where X = 3, 4, or 5) |
Switching |
State | SX0 | SX1 | SX2 | SX3 | SX4 | SX5 | | SX7 |
P2 | ||||||||
1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | |
|
0 | 1 | 1 | 1 | 1 | 0 | 0 | 0 |
|
0 | 0 | 1 | 1 | 1 | 1 | 0 | 0 |
|
0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 |
|
0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 |
TABLE 3 | |||
V2 (V DC) | V3 (V AC) | ||
21 kV | 13.8 kV | ||
10 kV | 6.6 kV | ||
5 kV | 3.3 kV | ||
1 kV | 600 V | ||
Claims (15)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US18/078,401 US11923725B2 (en) | 2012-07-09 | 2022-12-09 | Transformerless multi-level medium-voltage uninterruptable power supply systems and methods |
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201261669665P | 2012-07-09 | 2012-07-09 | |
US201261670057P | 2012-07-10 | 2012-07-10 | |
PCT/US2013/049818 WO2014011706A1 (en) | 2012-07-09 | 2013-07-09 | Transformerless multi-level medium-voltage uninterruptible power supply (ups) systems and methods |
US14/594,073 US9985473B2 (en) | 2012-07-09 | 2015-01-09 | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) system |
US15/991,700 US10873208B2 (en) | 2012-07-09 | 2018-05-29 | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) systems and methods |
US17/124,491 US11539236B2 (en) | 2012-07-09 | 2020-12-16 | Multi-level uninterruptable power supply systems and methods |
US18/078,401 US11923725B2 (en) | 2012-07-09 | 2022-12-09 | Transformerless multi-level medium-voltage uninterruptable power supply systems and methods |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/124,491 Continuation US11539236B2 (en) | 2012-07-09 | 2020-12-16 | Multi-level uninterruptable power supply systems and methods |
Publications (2)
Publication Number | Publication Date |
---|---|
US20230108992A1 US20230108992A1 (en) | 2023-04-06 |
US11923725B2 true US11923725B2 (en) | 2024-03-05 |
Family
ID=49916519
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/594,073 Active 2035-01-11 US9985473B2 (en) | 2012-07-09 | 2015-01-09 | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) system |
US15/991,700 Active 2033-12-11 US10873208B2 (en) | 2012-07-09 | 2018-05-29 | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) systems and methods |
US17/124,491 Active US11539236B2 (en) | 2012-07-09 | 2020-12-16 | Multi-level uninterruptable power supply systems and methods |
US18/078,401 Active US11923725B2 (en) | 2012-07-09 | 2022-12-09 | Transformerless multi-level medium-voltage uninterruptable power supply systems and methods |
Family Applications Before (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/594,073 Active 2035-01-11 US9985473B2 (en) | 2012-07-09 | 2015-01-09 | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) system |
US15/991,700 Active 2033-12-11 US10873208B2 (en) | 2012-07-09 | 2018-05-29 | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) systems and methods |
US17/124,491 Active US11539236B2 (en) | 2012-07-09 | 2020-12-16 | Multi-level uninterruptable power supply systems and methods |
Country Status (2)
Country | Link |
---|---|
US (4) | US9985473B2 (en) |
WO (1) | WO2014011706A1 (en) |
Families Citing this family (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014011706A1 (en) | 2012-07-09 | 2014-01-16 | Inertech Ip Llc | Transformerless multi-level medium-voltage uninterruptible power supply (ups) systems and methods |
US9876354B2 (en) | 2014-05-21 | 2018-01-23 | Eaton Corporation | UPS systems and methods using coordinated static switch and inverter operation for generator walk-in |
WO2016065087A1 (en) | 2014-10-21 | 2016-04-28 | Inertech Ip Llc | Systems and methods for controlling multi-level diode-clamped inverters using space vector pulse width modulation (svpwm) |
US9582016B2 (en) * | 2015-02-05 | 2017-02-28 | Silicon Laboratories Inc. | Boost converter with capacitive boost stages |
US11146170B2 (en) * | 2015-02-27 | 2021-10-12 | The University Of Hong Kong | Plural stages switching capacitor converter |
US20190067958A1 (en) * | 2015-04-03 | 2019-02-28 | Charles Zimnicki | Hybrid Power Supply Unit For Audio Amplifier |
US10348125B2 (en) | 2015-04-28 | 2019-07-09 | Inertech Ip Llc | Devices and methods for reliable power supply for electronic devices |
CN106130084B (en) * | 2015-05-04 | 2019-02-01 | 储盈新能源科技(上海)有限公司 | Uninterruptible power supply |
FR3038796B1 (en) * | 2015-07-09 | 2017-08-11 | Moteurs Leroy-Somer | ENERGY GENERATING SYSTEM WITH IMPROVED TREATMENT OF LOAD IMPACTS, DELAYS AND HARMONICS |
US10141832B2 (en) * | 2015-07-10 | 2018-11-27 | Maxim Integrated Products, Inc. | Systems and methods for reducing switch stress in switched mode power supplies |
US9564834B1 (en) * | 2015-07-27 | 2017-02-07 | Hon Hai Precision Industry Co., Ltd. | Alternating current to direct current converter system |
US9831717B2 (en) | 2015-09-16 | 2017-11-28 | General Electric Company | Systems and methods for operating uninterruptible power supplies |
JP6538874B2 (en) * | 2015-12-01 | 2019-07-03 | 東芝三菱電機産業システム株式会社 | Uninterruptible power system |
JP6121018B1 (en) * | 2016-03-23 | 2017-04-26 | 三菱電機株式会社 | DC / DC converter |
DE102017206254A1 (en) * | 2016-04-13 | 2017-10-19 | Dialog Semiconductor (Uk) Limited | DC-DC conversion for multi-cell batteries |
US9935549B2 (en) * | 2016-07-08 | 2018-04-03 | Toshiba International Corporation | Multi-switch power converter |
CN106451507B (en) * | 2016-10-11 | 2018-12-04 | 许昌许继软件技术有限公司 | The microgrid power balance method and device of integrated application super capacitor and battery |
CN108092371B (en) * | 2016-11-15 | 2020-04-03 | 华为技术有限公司 | Charging and discharging device |
WO2018102689A1 (en) * | 2016-12-01 | 2018-06-07 | Integrated Device Technology, Inc. | Battery charging system |
JP6898447B2 (en) * | 2016-12-01 | 2021-07-07 | インテグレーテッド・デバイス・テクノロジー・インコーポレーテッド | Battery charging system |
US10554061B2 (en) | 2016-12-01 | 2020-02-04 | Integrated Device Technology, Inc. | Battery charging system |
WO2018135045A1 (en) * | 2017-01-23 | 2018-07-26 | 三菱電機株式会社 | Power conversion device and power conversion system |
US20170201170A1 (en) * | 2017-03-26 | 2017-07-13 | Ahmed Fayez Abu-Hajar | Method for generating highly efficient harmonics free dc to ac inverters |
CN109755973B (en) * | 2017-11-01 | 2022-06-24 | 北京德意新能科技有限公司 | Flexible parallel device suitable for energy storage battery |
WO2019097746A1 (en) * | 2017-11-16 | 2019-05-23 | 三菱電機株式会社 | Power conversion device |
US10554128B2 (en) * | 2018-01-05 | 2020-02-04 | Futurewei Technologies, Inc. | Multi-level boost converter |
CN109245557B (en) * | 2018-09-06 | 2021-10-01 | 南京南瑞继保电气有限公司 | Modular converter device, combined converter and control method |
CN110581596B (en) * | 2019-08-30 | 2022-03-11 | 漳州科华电气技术有限公司 | Multi-source energy storage direct current power supply device and UPS equipment |
JP2023501305A (en) | 2019-11-06 | 2023-01-18 | エフィシェント・パワー・コンバージョン・コーポレイション | Multilevel converter with voltage divider for precharging flying capacitors |
CN112953202B (en) * | 2021-03-03 | 2023-10-20 | 华为数字能源技术有限公司 | Voltage conversion circuit and power supply system |
US11824463B1 (en) * | 2022-04-29 | 2023-11-21 | Novatek Microelectronics Corp. | Multiple output voltage generator |
US20240055891A1 (en) * | 2022-08-11 | 2024-02-15 | Milwaukee Electric Tool Corporation | Portable power supply with bidirectional charging and passthrough |
Citations (157)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5200644A (en) | 1988-05-31 | 1993-04-06 | Kabushiki Kaisha Toshiba | Air conditioning system having battery for increasing efficiency |
US5270913A (en) * | 1992-04-06 | 1993-12-14 | D.C. Transformation, Inc. | Compact and efficient transformerless power conversion system |
US5343079A (en) | 1991-02-25 | 1994-08-30 | Regents Of The University Of Minnesota | Standby power supply with load-current harmonics neutralizer |
US5612580A (en) | 1995-10-10 | 1997-03-18 | Northrop Grumman Corporation | Uninterruptible power system |
US5715693A (en) | 1996-07-19 | 1998-02-10 | Sunpower, Inc. | Refrigeration circuit having series evaporators and modulatable compressor |
US5818379A (en) | 1996-03-19 | 1998-10-06 | Samsung Electronics, Co., Ltd. | Flash analog to digital (A/D) converter with reduced number of comparators |
US6116048A (en) | 1997-02-18 | 2000-09-12 | Hebert; Thomas H. | Dual evaporator for indoor units and method therefor |
US6160722A (en) * | 1999-08-13 | 2000-12-12 | Powerware Corporation | Uninterruptible power supplies with dual-sourcing capability and methods of operation thereof |
US6201720B1 (en) | 2000-02-18 | 2001-03-13 | Powerware Corporation | Apparatus and methods for space-vector domain control in uninterruptible power supplies |
US20020014802A1 (en) | 2000-05-31 | 2002-02-07 | Cratty William E. | Power system utilizing a DC bus |
US6374627B1 (en) | 2001-01-09 | 2002-04-23 | Donald J. Schumacher | Data center cooling system |
US6404655B1 (en) * | 1999-12-07 | 2002-06-11 | Semikron, Inc. | Transformerless 3 phase power inverter |
US6420793B1 (en) * | 2000-09-21 | 2002-07-16 | Ford Global Technologies, Inc. | Power delivery circuit with boost for energetic starting in a pulsed charge starter/alternator system |
US20020172007A1 (en) | 2001-05-16 | 2002-11-21 | Pautsch Gregory W. | Spray evaporative cooling system and method |
US20030061824A1 (en) | 2000-04-04 | 2003-04-03 | Joseph Marsala | Pumped liquid cooling system using a phase change refrigerant |
US20030076696A1 (en) | 2001-10-18 | 2003-04-24 | Delta Electronics, Inc. | Device of uninterruptible power supply |
US6574104B2 (en) | 2001-10-05 | 2003-06-03 | Hewlett-Packard Development Company L.P. | Smart cooling of data centers |
US6640561B2 (en) | 2000-03-16 | 2003-11-04 | Rc Group S.P.A. | Chilling unit with “free-cooling”, designed to operate also with variable flow rate; system and process |
US20040084965A1 (en) | 2002-10-22 | 2004-05-06 | Welches Richard Shaun | Hybrid variable speed generator/uninterruptible power supply power converter |
US6772604B2 (en) | 2002-10-03 | 2004-08-10 | Hewlett-Packard Development Company, L.P. | Cooling of data centers |
US20040184232A1 (en) | 2003-03-19 | 2004-09-23 | James Fink | Data center cooling system |
US6826922B2 (en) | 2002-08-02 | 2004-12-07 | Hewlett-Packard Development Company, L.P. | Cooling system |
US6879053B1 (en) | 2002-10-22 | 2005-04-12 | Youtility, Inc. | Transformerless, load adaptive speed controller |
US20050162137A1 (en) * | 2004-01-23 | 2005-07-28 | Tracy John G. | Power conversion apparatus and methods using DC bus shifting |
US6924993B2 (en) | 2003-09-24 | 2005-08-02 | General Motors Corporation | Method and apparatus for controlling a stand-alone 4-leg voltage source inverter |
US20050200205A1 (en) | 2004-01-30 | 2005-09-15 | Winn David W. | On-site power generation system with redundant uninterruptible power supply |
US6950321B2 (en) | 2003-09-24 | 2005-09-27 | General Motors Corporation | Active damping control for L-C output filters in three phase four-leg inverters |
US20050231039A1 (en) | 1997-09-23 | 2005-10-20 | Hunt Technologies, Inc. | Low frequency bilateral communication over distributed power lines |
US7005759B2 (en) * | 2003-02-18 | 2006-02-28 | Delta Electronics, Inc. | Integrated converter having three-phase power factor correction |
US20060061334A1 (en) | 2004-09-17 | 2006-03-23 | Pollack Jerry J | Apparatus and method for transient and uninterruptible power |
US7046514B2 (en) | 2003-03-19 | 2006-05-16 | American Power Conversion Corporation | Data center cooling |
US7106590B2 (en) | 2003-12-03 | 2006-09-12 | International Business Machines Corporation | Cooling system and method employing multiple dedicated coolant conditioning units for cooling multiple electronics subsystems |
US20060221523A1 (en) | 2005-03-31 | 2006-10-05 | Silvio Colombi | Control system, method and product for uninterruptible power supply |
US20060245216A1 (en) * | 2005-04-15 | 2006-11-02 | Rockwell Automation, Inc. | DC voltage balance control for three-level NPC power converters with even-order harmonic elimination scheme |
US20060261748A1 (en) * | 2004-07-28 | 2006-11-23 | Yasuhiro Nukisato | Discharge lamp ballast apparatus |
US20070008745A1 (en) * | 2005-07-08 | 2007-01-11 | Bio-Rad Laboratories, Inc. | Wide range power supply |
US20070064363A1 (en) | 2005-09-16 | 2007-03-22 | American Power Conversion Corporation | Apparatus for and method of UPS operation |
US20070182383A1 (en) | 2005-12-30 | 2007-08-09 | Korea Electrotechnology Research Institute | Electric power converting device and power converting method for controlling doubly-fed induction generator |
US20070210652A1 (en) * | 2006-03-10 | 2007-09-13 | Eaton Power Quality Corporation | Nested Redundant Uninterruptible Power Supply Apparatus and Methods |
US20070227710A1 (en) | 2006-04-03 | 2007-10-04 | Belady Christian L | Cooling system for electrical devices |
US20070236187A1 (en) * | 2006-04-07 | 2007-10-11 | Yuan Ze University | High-performance solar photovoltaic ( PV) energy conversion system |
US20080088183A1 (en) | 2002-12-06 | 2008-04-17 | Electric Power Research Institute, Inc. | Integrated Closed Loop Control Method and Apparatus for Combined Uninterruptible Power Supply and Generator System |
US20080130332A1 (en) | 2006-11-30 | 2008-06-05 | Eaton Power Quality Corporation | Power Supply Apparatus, Methods and Computer Program Products Using D-Q Domain Based Synchronization Techniques |
US7406839B2 (en) | 2005-10-05 | 2008-08-05 | American Power Conversion Corporation | Sub-cooling unit for cooling system and method |
US7418825B1 (en) | 2004-11-19 | 2008-09-02 | American Power Conversion Corporation | IT equipment cooling |
US20080239775A1 (en) * | 2007-03-27 | 2008-10-02 | Eaton Power Quality Corporation | Power Converter Apparatus and Methods Using Neutral Coupling Circuits with Interleaved Operation |
JP2008287733A (en) | 2008-06-19 | 2008-11-27 | Hitachi Ltd | Liquid cooling system |
US20080304300A1 (en) | 2007-06-06 | 2008-12-11 | General Electric Company | Power conversion system with galvanically isolated high frequency link |
US7477514B2 (en) | 2007-05-04 | 2009-01-13 | International Business Machines Corporation | Method of facilitating cooling of electronics racks of a data center employing multiple cooling stations |
US20090019535A1 (en) | 2007-07-10 | 2009-01-15 | Ragingwire Enterprise Solutions, Inc. | Method and remote system for creating a customized server infrastructure in real time |
US20090021081A1 (en) * | 2007-07-18 | 2009-01-22 | Jacobson Boris S | Methods and apparatus for three-phase inverter with reduced energy storage |
US20090021082A1 (en) | 2007-07-20 | 2009-01-22 | Eaton Power Quality Corporation | Generator Systems and Methods Using Timing Reference Signal to Control Generator Synchronization |
US20090034304A1 (en) * | 2007-08-04 | 2009-02-05 | Sma Solar Technology Ag | Inverter for grounded direct current source, more specifically for a photovoltaic generator |
US20090051344A1 (en) | 2007-08-24 | 2009-02-26 | Lumsden John L | Triac/scr-based energy savings device, system and method |
US20090086428A1 (en) | 2007-09-27 | 2009-04-02 | International Business Machines Corporation | Docking station with hybrid air and liquid cooling of an electronics rack |
CN101442893A (en) | 2007-11-19 | 2009-05-27 | 国际商业机器公司 | System and method for facilitating cooling of a liquid-cooled electronics rack |
US20090154096A1 (en) | 2007-12-17 | 2009-06-18 | International Business Machines Corporation | Apparatus and method for facilitating cooling of an electronics system |
US7569954B2 (en) | 2002-09-20 | 2009-08-04 | Siemens Aktiengesellschaft | Redundant cooling system with two cooling circuits for an electric motor |
US20090212631A1 (en) | 2008-02-22 | 2009-08-27 | Liebert Corporation | Substation based high voltage uninterruptible power supply |
US20090302616A1 (en) | 2006-11-16 | 2009-12-10 | Peterson Mitchell E | Electric power generation system controlled to reduce perception of operational changes |
US20090315404A1 (en) | 2008-06-19 | 2009-12-24 | Sma Solar Technology Ag | Solar power plant |
US20100008105A1 (en) * | 2008-07-09 | 2010-01-14 | Sma Solar Technology Ag | Dc/dc converter |
US7649281B2 (en) * | 2006-04-17 | 2010-01-19 | Delta Electronics, Inc. | Low power loss uninterruptible power supply |
US7660116B2 (en) | 2008-04-21 | 2010-02-09 | International Business Machines Corporation | Rack with integrated rear-door heat exchanger |
US20100032142A1 (en) | 2008-08-11 | 2010-02-11 | Sun Microsystems, Inc. | Liquid cooled rack with optimized air flow rate and liquid coolant flow |
US20100094472A1 (en) | 2008-10-14 | 2010-04-15 | Woytowitz Peter J | Irrigation System With Soil Moisture Based Seasonal Watering Adjustment |
US7706163B2 (en) * | 2006-11-10 | 2010-04-27 | Delta Electronics, Inc. | Three-level AC generating circuit and control method thereof |
US20100136895A1 (en) | 2008-08-19 | 2010-06-03 | Turner Logistics | Data center and methods for cooling thereof |
US7730731B1 (en) | 2005-11-01 | 2010-06-08 | Hewlett-Packard Development Company, L.P. | Refrigeration system with serial evaporators |
US7738251B2 (en) | 2006-06-01 | 2010-06-15 | Google Inc. | Modular computing environments |
US20100188869A1 (en) * | 2007-07-26 | 2010-07-29 | Fredette Steven J | Power system having ac and dc power sources |
US20100201194A1 (en) | 2004-01-23 | 2010-08-12 | American Power Conversion Corporation | Methods and apparatus for providing uninterruptible power |
US20100207463A1 (en) | 2007-04-13 | 2010-08-19 | Repower Systems Ag | Method for operating a wind power plant with excess voltage in the grid |
US7804687B2 (en) | 2008-08-08 | 2010-09-28 | Oracle America, Inc. | Liquid-cooled rack with pre-cooler and post-cooler heat exchangers used for EMI shielding |
US20100264882A1 (en) | 2007-02-16 | 2010-10-21 | O2Micro, Inc. | Circuits and methods for battery charging |
US20100300650A1 (en) | 2009-06-02 | 2010-12-02 | American Power Conversion Corporation | Container air handling unit and cooling method |
US7855890B2 (en) | 2008-02-13 | 2010-12-21 | Hitachi Plant Technologies, Ltd. | Cooling system for electronic equipment |
US7864527B1 (en) | 2004-03-31 | 2011-01-04 | Google Inc. | Systems and methods for close coupled cooling |
US7903409B2 (en) | 2007-07-18 | 2011-03-08 | Hewlett-Packard Development Company, L.P. | System and method for cooling an electronic device |
US7903404B2 (en) | 2009-04-29 | 2011-03-08 | Hewlett-Packard Development Company, L.P. | Data centers |
US7907406B1 (en) | 2009-09-28 | 2011-03-15 | International Business Machines Corporation | System and method for standby mode cooling of a liquid-cooled electronics rack |
US7957144B2 (en) | 2007-03-16 | 2011-06-07 | International Business Machines Corporation | Heat exchange system for blade server systems and method |
US20110141786A1 (en) * | 2010-09-29 | 2011-06-16 | General Electric Company | Dc-link voltage balancing system and method for multilevel converters |
US20110141779A1 (en) * | 2009-12-11 | 2011-06-16 | Joseph Alan | Boost Multilevel Inverter System |
US7963119B2 (en) | 2007-11-26 | 2011-06-21 | International Business Machines Corporation | Hybrid air and liquid coolant conditioning unit for facilitating cooling of one or more electronics racks of a data center |
US8000103B2 (en) | 2007-12-19 | 2011-08-16 | Clustered Systems Company | Cooling system for contact cooled electronic modules |
US20110198057A1 (en) | 2010-02-12 | 2011-08-18 | Lange Torben B | Heat dissipation apparatus for data center |
US8031468B2 (en) | 2009-06-03 | 2011-10-04 | American Power Conversion Corporation | Hot aisle containment cooling unit and method for cooling |
US20110265983A1 (en) | 2009-01-08 | 2011-11-03 | Leaneco Aps | Cooling apparatus and method |
US20110278934A1 (en) * | 2010-05-14 | 2011-11-17 | American Power Conversion Corporation | Digital control method for operating the ups systems in parallel |
US20110313576A1 (en) | 2010-06-17 | 2011-12-22 | Mark Randal Nicewonger | System and method for flowing fluids through electronic chassis modules |
US8093746B2 (en) | 2009-12-16 | 2012-01-10 | General Electric Company | Control of four-leg transformerless uninterruptible power supply |
CN102334396A (en) | 2009-01-28 | 2012-01-25 | 美国能量变换公司 | Hot aisle containment cooling system and method |
US20120019230A1 (en) * | 2010-07-20 | 2012-01-26 | Vincotech Gmbh | Dc/dc converter circuit and method for controlling a dc/dc converter circuit |
US8120916B2 (en) | 2009-09-17 | 2012-02-21 | International Business Machines Corporation | Facilitating cooling of an electronics rack employing water vapor compression system |
US8118084B2 (en) | 2007-05-01 | 2012-02-21 | Liebert Corporation | Heat exchanger and method for use in precision cooling systems |
US8146374B1 (en) | 2009-02-13 | 2012-04-03 | Source IT Energy, LLC | System and method for efficient utilization of energy generated by a utility plant |
US20120103591A1 (en) | 2009-07-09 | 2012-05-03 | Hewlett-Packard Development Company, L.P. | Cooling apparatus |
US8189334B2 (en) | 2010-05-26 | 2012-05-29 | International Business Machines Corporation | Dehumidifying and re-humidifying cooling apparatus and method for an electronics rack |
US8208258B2 (en) | 2009-09-09 | 2012-06-26 | International Business Machines Corporation | System and method for facilitating parallel cooling of liquid-cooled electronics racks |
US8212401B2 (en) | 2007-08-03 | 2012-07-03 | Stratascale, Inc. | Redundant isolation and bypass of critical power equipment |
US8212409B2 (en) * | 2008-03-22 | 2012-07-03 | Sma Solar Technology Ag | Method for activating a multi-string inverter for photovoltaic plants |
US20120174612A1 (en) | 2010-05-21 | 2012-07-12 | Liebert Corporation | Computer Room Air Conditioner With Pre-Cooler |
US8228046B2 (en) * | 2009-06-16 | 2012-07-24 | American Power Conversion Corporation | Apparatus and method for operating an uninterruptible power supply |
US8253424B2 (en) * | 2009-09-11 | 2012-08-28 | Sma Solar Technology Ag | Topology surveying a series of capacitors |
US8261565B2 (en) | 2003-12-05 | 2012-09-11 | Liebert Corporation | Cooling system for high density heat load |
US8289710B2 (en) | 2006-02-16 | 2012-10-16 | Liebert Corporation | Liquid cooling systems for server applications |
US8294297B2 (en) | 2007-08-03 | 2012-10-23 | Ragingwire Enterprise Solutions, Inc. | Scalable distributed redundancy |
US8297069B2 (en) | 2009-03-19 | 2012-10-30 | Vette Corporation | Modular scalable coolant distribution unit |
US8320125B1 (en) | 2007-06-29 | 2012-11-27 | Exaflop Llc | Modular data center cooling |
US20120319495A1 (en) * | 2010-03-03 | 2012-12-20 | Sma Solar Technology Ag | Power Inverter with Multi-Fed On-Board Power Supply |
US8351200B2 (en) | 2007-11-19 | 2013-01-08 | International Business Machines Corporation | Convergence of air water cooling of an electronics rack and a computer room in a single unit |
US8387687B2 (en) | 2000-03-21 | 2013-03-05 | Liebert Corporation | Method and apparatus for cooling electronic enclosures |
US8405977B2 (en) | 2010-12-30 | 2013-03-26 | Hon Hai Precision Industry Co., Ltd. | Container data center |
US20130082636A1 (en) * | 2011-09-29 | 2013-04-04 | Daihen Corporation | Signal processor, filter, control circuit for power converter circuit, interconnection inverter system and pwm converter system |
US8427010B2 (en) * | 2009-05-29 | 2013-04-23 | General Electric Company | DC-to-AC power conversion system and method |
DE102012218873A1 (en) | 2011-10-31 | 2013-05-02 | International Business Machines Corporation | Multi-rack unit with shared cooling device |
US8456840B1 (en) | 2007-07-06 | 2013-06-04 | Exaflop Llc | Modular data center cooling |
US8457938B2 (en) | 2007-12-05 | 2013-06-04 | International Business Machines Corporation | Apparatus and method for simulating one or more operational characteristics of an electronics rack |
US8472182B2 (en) | 2010-07-28 | 2013-06-25 | International Business Machines Corporation | Apparatus and method for facilitating dissipation of heat from a liquid-cooled electronics rack |
US8514575B2 (en) | 2010-11-16 | 2013-08-20 | International Business Machines Corporation | Multimodal cooling apparatus for an electronic system |
JP5308750B2 (en) | 2008-03-26 | 2013-10-09 | 株式会社Nttファシリティーズ | Rack air conditioning system |
US8583290B2 (en) | 2009-09-09 | 2013-11-12 | International Business Machines Corporation | Cooling system and method minimizing power consumption in cooling liquid-cooled electronics racks |
US8624561B1 (en) * | 2009-12-29 | 2014-01-07 | Solarbridge Technologies, Inc. | Power conversion having energy storage with dynamic reference |
US20140009988A1 (en) | 2011-02-01 | 2014-01-09 | Power-One Italy S.P.A. | Modulation of Multi-Phase Inverter |
WO2014011706A1 (en) | 2012-07-09 | 2014-01-16 | Inertech Ip Llc | Transformerless multi-level medium-voltage uninterruptible power supply (ups) systems and methods |
EP2722978A2 (en) | 2012-10-22 | 2014-04-23 | Hamilton Sundstrand Corporation | System and method for common-mode elimination in a multi-level converter |
US8730691B2 (en) * | 2011-05-11 | 2014-05-20 | Eaton Corporation | Power conversion apparatus and methods employing variable-level inverters |
US20140152109A1 (en) | 2012-11-30 | 2014-06-05 | General Electric Company | Medium voltage uninterruptible power supply |
US8763414B2 (en) | 2008-03-31 | 2014-07-01 | Google Inc. | Warm floor data center |
US8783052B2 (en) | 2010-11-04 | 2014-07-22 | International Business Machines Corporation | Coolant-buffered, vapor-compression refrigeration with thermal storage and compressor cycling |
US8797740B2 (en) | 2011-10-31 | 2014-08-05 | International Business Machines Corporation | Multi-rack assembly method with shared cooling unit |
US8816533B2 (en) | 2011-02-16 | 2014-08-26 | Eaton Corporation | Uninterruptible power supply systems and methods using an isolated neutral reference |
US8836258B2 (en) * | 2009-04-15 | 2014-09-16 | Mitsubishi Electric Corporation | Inverter device, motor driving device, refrigerating air conditioner, and power generation system |
US20140334211A1 (en) * | 2013-05-07 | 2014-11-13 | University Of Central Florida Research Foundation, Inc. | Power inverter implementing phase skipping control |
US20140368043A1 (en) | 2013-06-14 | 2014-12-18 | General Electric Company | Systems and methods for grid interactive ups |
US20150021998A1 (en) * | 2013-07-18 | 2015-01-22 | Solantro Semiconductor Corp. | Stabilized power generation |
US20150035358A1 (en) | 2013-08-05 | 2015-02-05 | Ragingwire Data Centers, Inc. | Electrical power management system and method |
US8976556B2 (en) * | 2012-07-12 | 2015-03-10 | Mitsubishi Electric Research Laboratories, Inc. | Space vector modulation for multilevel inverters |
US20150155712A1 (en) * | 2013-09-09 | 2015-06-04 | Inertech Ip Llc | Multi-level medium voltage data center static synchronous compensator (dcstatcom) for active and reactive power control of data centers connected with grid energy storage and smart green distributed energy sources |
US20150280608A1 (en) * | 2014-03-26 | 2015-10-01 | Solaredge Technologies, Ltd | Multi-level inverter |
US9203323B2 (en) * | 2011-09-22 | 2015-12-01 | Renewable Power Conversion, Inc. | Very high efficiency uninterruptible power supply |
US9214874B2 (en) * | 2012-07-31 | 2015-12-15 | Yashomani Y. Kolhatkar | Intelligent level transition systems and methods for transformerless uninterruptible power supply |
US20150370278A1 (en) * | 2014-06-20 | 2015-12-24 | Boe Technology Group Co., Ltd. | Maximum Power Point Tracking Method and Device, and Photovoltaic Power Generation System |
US9362814B2 (en) * | 2011-12-23 | 2016-06-07 | North Carolina State University | Switched-capacitor DC-DC converter |
US20160294188A1 (en) | 2015-03-30 | 2016-10-06 | Sonnenbatterie Gmbh | Energy supply system and conductor loop enclosure |
US9520800B2 (en) * | 2014-01-09 | 2016-12-13 | Rockwell Automation Technologies, Inc. | Multilevel converter systems and methods with reduced common mode voltage |
US20170028859A1 (en) * | 2015-07-30 | 2017-02-02 | Lsis Co., Ltd. | Apparatus for controlling charging/discharging of battery |
US20170117822A1 (en) * | 2015-10-23 | 2017-04-27 | Majid Pahlevaninezhad | Dynamic maximum efficiency tracker for pv micro-inverter |
US9793752B1 (en) | 2010-06-28 | 2017-10-17 | Amazon Technologies, Inc. | Reserve power system for data center |
US9912251B2 (en) * | 2014-10-21 | 2018-03-06 | Inertech Ip Llc | Systems and methods for controlling multi-level diode-clamped inverters using space vector pulse width modulation (SVPWM) |
US10014713B1 (en) | 2014-07-31 | 2018-07-03 | Amazon Technologies, Inc. | Redundant secondary power support system |
US10033220B1 (en) | 2014-08-19 | 2018-07-24 | Amazon Technologies, Inc. | High-voltage energy storage system |
US20180269782A1 (en) | 2016-12-22 | 2018-09-20 | Inertech Ip Llc | Systems and Methods for Isolated Low Voltage Energy Storage for Data Centers |
US10193380B2 (en) * | 2015-01-13 | 2019-01-29 | Inertech Ip Llc | Power sources and systems utilizing a common ultra-capacitor and battery hybrid energy storage system for both uninterruptible power supply and generator start-up functions |
US20190260306A1 (en) * | 2017-01-11 | 2019-08-22 | Murata Manufacturing Co., Ltd. | Power converter |
US10931190B2 (en) * | 2015-10-22 | 2021-02-23 | Inertech Ip Llc | Systems and methods for mitigating harmonics in electrical systems by using active and passive filtering techniques |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6515883B2 (en) * | 2001-03-28 | 2003-02-04 | Powerware Corporation | Single-stage power converter and an uninterruptible power supply using same |
US6737762B2 (en) * | 2001-10-26 | 2004-05-18 | Onan Corporation | Generator with DC boost for uninterruptible power supply system or for enhanced load pickup |
JP2005176461A (en) * | 2003-12-09 | 2005-06-30 | Matsushita Electric Ind Co Ltd | Direct-current uninterruptible power supply unit |
WO2006128008A2 (en) * | 2005-05-26 | 2006-11-30 | Farmer Emory Farmer | Hybrid uninterruptible power supply system |
-
2013
- 2013-07-09 WO PCT/US2013/049818 patent/WO2014011706A1/en active Application Filing
-
2015
- 2015-01-09 US US14/594,073 patent/US9985473B2/en active Active
-
2018
- 2018-05-29 US US15/991,700 patent/US10873208B2/en active Active
-
2020
- 2020-12-16 US US17/124,491 patent/US11539236B2/en active Active
-
2022
- 2022-12-09 US US18/078,401 patent/US11923725B2/en active Active
Patent Citations (200)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5200644A (en) | 1988-05-31 | 1993-04-06 | Kabushiki Kaisha Toshiba | Air conditioning system having battery for increasing efficiency |
US5343079A (en) | 1991-02-25 | 1994-08-30 | Regents Of The University Of Minnesota | Standby power supply with load-current harmonics neutralizer |
US5764501A (en) * | 1992-04-06 | 1998-06-09 | D.C. Transformation, Inc. | Compact and efficient power transfer system and method |
US5270913A (en) * | 1992-04-06 | 1993-12-14 | D.C. Transformation, Inc. | Compact and efficient transformerless power conversion system |
US5357419A (en) * | 1992-04-06 | 1994-10-18 | D.C. Transformation Inc. | Compact and efficient transformerless power conversion system |
US5561597A (en) * | 1992-04-06 | 1996-10-01 | D.C. Transformation, Inc. | Compact and efficient transformerless power conversion system |
US5612580A (en) | 1995-10-10 | 1997-03-18 | Northrop Grumman Corporation | Uninterruptible power system |
US5818379A (en) | 1996-03-19 | 1998-10-06 | Samsung Electronics, Co., Ltd. | Flash analog to digital (A/D) converter with reduced number of comparators |
US5715693A (en) | 1996-07-19 | 1998-02-10 | Sunpower, Inc. | Refrigeration circuit having series evaporators and modulatable compressor |
US6116048A (en) | 1997-02-18 | 2000-09-12 | Hebert; Thomas H. | Dual evaporator for indoor units and method therefor |
US20050231039A1 (en) | 1997-09-23 | 2005-10-20 | Hunt Technologies, Inc. | Low frequency bilateral communication over distributed power lines |
US6160722A (en) * | 1999-08-13 | 2000-12-12 | Powerware Corporation | Uninterruptible power supplies with dual-sourcing capability and methods of operation thereof |
US6404655B1 (en) * | 1999-12-07 | 2002-06-11 | Semikron, Inc. | Transformerless 3 phase power inverter |
US6201720B1 (en) | 2000-02-18 | 2001-03-13 | Powerware Corporation | Apparatus and methods for space-vector domain control in uninterruptible power supplies |
US6640561B2 (en) | 2000-03-16 | 2003-11-04 | Rc Group S.P.A. | Chilling unit with “free-cooling”, designed to operate also with variable flow rate; system and process |
US8387687B2 (en) | 2000-03-21 | 2013-03-05 | Liebert Corporation | Method and apparatus for cooling electronic enclosures |
US20030061824A1 (en) | 2000-04-04 | 2003-04-03 | Joseph Marsala | Pumped liquid cooling system using a phase change refrigerant |
US20020014802A1 (en) | 2000-05-31 | 2002-02-07 | Cratty William E. | Power system utilizing a DC bus |
US6420793B1 (en) * | 2000-09-21 | 2002-07-16 | Ford Global Technologies, Inc. | Power delivery circuit with boost for energetic starting in a pulsed charge starter/alternator system |
US6374627B1 (en) | 2001-01-09 | 2002-04-23 | Donald J. Schumacher | Data center cooling system |
US20020172007A1 (en) | 2001-05-16 | 2002-11-21 | Pautsch Gregory W. | Spray evaporative cooling system and method |
US6574104B2 (en) | 2001-10-05 | 2003-06-03 | Hewlett-Packard Development Company L.P. | Smart cooling of data centers |
US20030076696A1 (en) | 2001-10-18 | 2003-04-24 | Delta Electronics, Inc. | Device of uninterruptible power supply |
US6826922B2 (en) | 2002-08-02 | 2004-12-07 | Hewlett-Packard Development Company, L.P. | Cooling system |
US7569954B2 (en) | 2002-09-20 | 2009-08-04 | Siemens Aktiengesellschaft | Redundant cooling system with two cooling circuits for an electric motor |
US6772604B2 (en) | 2002-10-03 | 2004-08-10 | Hewlett-Packard Development Company, L.P. | Cooling of data centers |
US6879053B1 (en) | 2002-10-22 | 2005-04-12 | Youtility, Inc. | Transformerless, load adaptive speed controller |
US20040084965A1 (en) | 2002-10-22 | 2004-05-06 | Welches Richard Shaun | Hybrid variable speed generator/uninterruptible power supply power converter |
US20080088183A1 (en) | 2002-12-06 | 2008-04-17 | Electric Power Research Institute, Inc. | Integrated Closed Loop Control Method and Apparatus for Combined Uninterruptible Power Supply and Generator System |
US7005759B2 (en) * | 2003-02-18 | 2006-02-28 | Delta Electronics, Inc. | Integrated converter having three-phase power factor correction |
US7046514B2 (en) | 2003-03-19 | 2006-05-16 | American Power Conversion Corporation | Data center cooling |
US7173820B2 (en) | 2003-03-19 | 2007-02-06 | American Power Conversion Corporation | Data center cooling |
EP1604263A2 (en) | 2003-03-19 | 2005-12-14 | American Power Conversion Corporation | Data center cooling system |
US6980433B2 (en) | 2003-03-19 | 2005-12-27 | American Power Conversion Corporation | Data center cooling system |
US7881057B2 (en) | 2003-03-19 | 2011-02-01 | American Power Conversion Corporation | Data center cooling |
US8780555B2 (en) | 2003-03-19 | 2014-07-15 | American Power Conversion Corporation | Data center cooling |
US20040184232A1 (en) | 2003-03-19 | 2004-09-23 | James Fink | Data center cooling system |
US7684193B2 (en) | 2003-03-19 | 2010-03-23 | American Power Conversion Corporation | Data center cooling |
JP5209584B2 (en) | 2003-03-19 | 2013-06-12 | アメリカン、パワー、コンバージョン、コーポレイション | Modular data center |
JP5244058B2 (en) | 2003-03-19 | 2013-07-24 | アメリカン、パワー、コンバージョン、コーポレイション | Modular data center and its system for limiting air mixing |
US6859366B2 (en) | 2003-03-19 | 2005-02-22 | American Power Conversion | Data center cooling system |
US8432690B2 (en) | 2003-03-19 | 2013-04-30 | American Power Conversion Corporation | Data center cooling |
US6950321B2 (en) | 2003-09-24 | 2005-09-27 | General Motors Corporation | Active damping control for L-C output filters in three phase four-leg inverters |
US6924993B2 (en) | 2003-09-24 | 2005-08-02 | General Motors Corporation | Method and apparatus for controlling a stand-alone 4-leg voltage source inverter |
US7106590B2 (en) | 2003-12-03 | 2006-09-12 | International Business Machines Corporation | Cooling system and method employing multiple dedicated coolant conditioning units for cooling multiple electronics subsystems |
US8261565B2 (en) | 2003-12-05 | 2012-09-11 | Liebert Corporation | Cooling system for high density heat load |
US20100201194A1 (en) | 2004-01-23 | 2010-08-12 | American Power Conversion Corporation | Methods and apparatus for providing uninterruptible power |
US20050162137A1 (en) * | 2004-01-23 | 2005-07-28 | Tracy John G. | Power conversion apparatus and methods using DC bus shifting |
US20050200205A1 (en) | 2004-01-30 | 2005-09-15 | Winn David W. | On-site power generation system with redundant uninterruptible power supply |
US7864527B1 (en) | 2004-03-31 | 2011-01-04 | Google Inc. | Systems and methods for close coupled cooling |
CN100584168C (en) | 2004-06-07 | 2010-01-20 | 美国能量变换公司 | Data center cooling system |
JP5301009B2 (en) | 2004-06-07 | 2013-09-25 | シュナイダー エレクトリック アイティー コーポレーション | Data center cooling |
CN101686629A (en) | 2004-06-07 | 2010-03-31 | 美国能量变换公司 | Data center cooling system |
JP5113203B2 (en) | 2004-06-07 | 2013-01-09 | アメリカン パワー コンバージョン コーポレイション | Data center cooling |
US20060261748A1 (en) * | 2004-07-28 | 2006-11-23 | Yasuhiro Nukisato | Discharge lamp ballast apparatus |
US20060061334A1 (en) | 2004-09-17 | 2006-03-23 | Pollack Jerry J | Apparatus and method for transient and uninterruptible power |
US7418825B1 (en) | 2004-11-19 | 2008-09-02 | American Power Conversion Corporation | IT equipment cooling |
US20060221523A1 (en) | 2005-03-31 | 2006-10-05 | Silvio Colombi | Control system, method and product for uninterruptible power supply |
US20060245216A1 (en) * | 2005-04-15 | 2006-11-02 | Rockwell Automation, Inc. | DC voltage balance control for three-level NPC power converters with even-order harmonic elimination scheme |
US20070008745A1 (en) * | 2005-07-08 | 2007-01-11 | Bio-Rad Laboratories, Inc. | Wide range power supply |
US20070064363A1 (en) | 2005-09-16 | 2007-03-22 | American Power Conversion Corporation | Apparatus for and method of UPS operation |
US7406839B2 (en) | 2005-10-05 | 2008-08-05 | American Power Conversion Corporation | Sub-cooling unit for cooling system and method |
US7730731B1 (en) | 2005-11-01 | 2010-06-08 | Hewlett-Packard Development Company, L.P. | Refrigeration system with serial evaporators |
US20070182383A1 (en) | 2005-12-30 | 2007-08-09 | Korea Electrotechnology Research Institute | Electric power converting device and power converting method for controlling doubly-fed induction generator |
US8289710B2 (en) | 2006-02-16 | 2012-10-16 | Liebert Corporation | Liquid cooling systems for server applications |
US20070210652A1 (en) * | 2006-03-10 | 2007-09-13 | Eaton Power Quality Corporation | Nested Redundant Uninterruptible Power Supply Apparatus and Methods |
US20070227710A1 (en) | 2006-04-03 | 2007-10-04 | Belady Christian L | Cooling system for electrical devices |
US20070236187A1 (en) * | 2006-04-07 | 2007-10-11 | Yuan Ze University | High-performance solar photovoltaic ( PV) energy conversion system |
US7649281B2 (en) * | 2006-04-17 | 2010-01-19 | Delta Electronics, Inc. | Low power loss uninterruptible power supply |
US8218322B2 (en) | 2006-06-01 | 2012-07-10 | Google Inc. | Modular computing environments |
US7738251B2 (en) | 2006-06-01 | 2010-06-15 | Google Inc. | Modular computing environments |
US7706163B2 (en) * | 2006-11-10 | 2010-04-27 | Delta Electronics, Inc. | Three-level AC generating circuit and control method thereof |
US20090302616A1 (en) | 2006-11-16 | 2009-12-10 | Peterson Mitchell E | Electric power generation system controlled to reduce perception of operational changes |
US20080130332A1 (en) | 2006-11-30 | 2008-06-05 | Eaton Power Quality Corporation | Power Supply Apparatus, Methods and Computer Program Products Using D-Q Domain Based Synchronization Techniques |
US20100264882A1 (en) | 2007-02-16 | 2010-10-21 | O2Micro, Inc. | Circuits and methods for battery charging |
US7957144B2 (en) | 2007-03-16 | 2011-06-07 | International Business Machines Corporation | Heat exchange system for blade server systems and method |
US20080239775A1 (en) * | 2007-03-27 | 2008-10-02 | Eaton Power Quality Corporation | Power Converter Apparatus and Methods Using Neutral Coupling Circuits with Interleaved Operation |
US7800924B2 (en) * | 2007-03-27 | 2010-09-21 | Eaton Corporation | Power converter apparatus and methods using neutral coupling circuits with interleaved operation |
US20100207463A1 (en) | 2007-04-13 | 2010-08-19 | Repower Systems Ag | Method for operating a wind power plant with excess voltage in the grid |
US8118084B2 (en) | 2007-05-01 | 2012-02-21 | Liebert Corporation | Heat exchanger and method for use in precision cooling systems |
US7660121B2 (en) | 2007-05-04 | 2010-02-09 | International Business Machines Corporation | System of facilitating cooling of electronics racks of a data center employing multiple cooling stations |
US7477514B2 (en) | 2007-05-04 | 2009-01-13 | International Business Machines Corporation | Method of facilitating cooling of electronics racks of a data center employing multiple cooling stations |
US20080304300A1 (en) | 2007-06-06 | 2008-12-11 | General Electric Company | Power conversion system with galvanically isolated high frequency link |
US8320125B1 (en) | 2007-06-29 | 2012-11-27 | Exaflop Llc | Modular data center cooling |
US8456840B1 (en) | 2007-07-06 | 2013-06-04 | Exaflop Llc | Modular data center cooling |
US20090019535A1 (en) | 2007-07-10 | 2009-01-15 | Ragingwire Enterprise Solutions, Inc. | Method and remote system for creating a customized server infrastructure in real time |
US20090019137A1 (en) | 2007-07-10 | 2009-01-15 | Ragingwire Enterprise Solutions, Inc. | Method and remote system for creating a customized server infrastructure in real time |
US8392035B2 (en) | 2007-07-18 | 2013-03-05 | Hewlett-Packard Development Company, L. P. | System and method for cooling an electronic device |
US20090021081A1 (en) * | 2007-07-18 | 2009-01-22 | Jacobson Boris S | Methods and apparatus for three-phase inverter with reduced energy storage |
US7903409B2 (en) | 2007-07-18 | 2011-03-08 | Hewlett-Packard Development Company, L.P. | System and method for cooling an electronic device |
US20090021082A1 (en) | 2007-07-20 | 2009-01-22 | Eaton Power Quality Corporation | Generator Systems and Methods Using Timing Reference Signal to Control Generator Synchronization |
US20100188869A1 (en) * | 2007-07-26 | 2010-07-29 | Fredette Steven J | Power system having ac and dc power sources |
US8212401B2 (en) | 2007-08-03 | 2012-07-03 | Stratascale, Inc. | Redundant isolation and bypass of critical power equipment |
US8294297B2 (en) | 2007-08-03 | 2012-10-23 | Ragingwire Enterprise Solutions, Inc. | Scalable distributed redundancy |
US20090034304A1 (en) * | 2007-08-04 | 2009-02-05 | Sma Solar Technology Ag | Inverter for grounded direct current source, more specifically for a photovoltaic generator |
US20090051344A1 (en) | 2007-08-24 | 2009-02-26 | Lumsden John L | Triac/scr-based energy savings device, system and method |
US20090086428A1 (en) | 2007-09-27 | 2009-04-02 | International Business Machines Corporation | Docking station with hybrid air and liquid cooling of an electronics rack |
US8351200B2 (en) | 2007-11-19 | 2013-01-08 | International Business Machines Corporation | Convergence of air water cooling of an electronics rack and a computer room in a single unit |
CN101442893A (en) | 2007-11-19 | 2009-05-27 | 国际商业机器公司 | System and method for facilitating cooling of a liquid-cooled electronics rack |
JP5243929B2 (en) | 2007-11-19 | 2013-07-24 | インターナショナル・ビジネス・マシーンズ・コーポレーション | Apparatus and method for facilitating cooling of liquid-cooled electronic equipment rack and data center including them |
US7963119B2 (en) | 2007-11-26 | 2011-06-21 | International Business Machines Corporation | Hybrid air and liquid coolant conditioning unit for facilitating cooling of one or more electronics racks of a data center |
US8689861B2 (en) | 2007-11-26 | 2014-04-08 | International Business Machines Corporation | Hybrid air and liquid coolant conditioning unit for facilitating cooling of one or more electronics racks of a data center |
US8457938B2 (en) | 2007-12-05 | 2013-06-04 | International Business Machines Corporation | Apparatus and method for simulating one or more operational characteristics of an electronics rack |
US20090154096A1 (en) | 2007-12-17 | 2009-06-18 | International Business Machines Corporation | Apparatus and method for facilitating cooling of an electronics system |
US8000103B2 (en) | 2007-12-19 | 2011-08-16 | Clustered Systems Company | Cooling system for contact cooled electronic modules |
US7855890B2 (en) | 2008-02-13 | 2010-12-21 | Hitachi Plant Technologies, Ltd. | Cooling system for electronic equipment |
US8199504B2 (en) | 2008-02-13 | 2012-06-12 | Hitachi Plant Technologies, Ltd. | Cooling system for electronic equipment |
US20090212631A1 (en) | 2008-02-22 | 2009-08-27 | Liebert Corporation | Substation based high voltage uninterruptible power supply |
US8212409B2 (en) * | 2008-03-22 | 2012-07-03 | Sma Solar Technology Ag | Method for activating a multi-string inverter for photovoltaic plants |
JP5308750B2 (en) | 2008-03-26 | 2013-10-09 | 株式会社Nttファシリティーズ | Rack air conditioning system |
US8763414B2 (en) | 2008-03-31 | 2014-07-01 | Google Inc. | Warm floor data center |
US7660116B2 (en) | 2008-04-21 | 2010-02-09 | International Business Machines Corporation | Rack with integrated rear-door heat exchanger |
US20090315404A1 (en) | 2008-06-19 | 2009-12-24 | Sma Solar Technology Ag | Solar power plant |
JP2008287733A (en) | 2008-06-19 | 2008-11-27 | Hitachi Ltd | Liquid cooling system |
US8138638B2 (en) * | 2008-07-09 | 2012-03-20 | Sma Solar Technology Ag | DC/DC converter |
US20100008105A1 (en) * | 2008-07-09 | 2010-01-14 | Sma Solar Technology Ag | Dc/dc converter |
US7804687B2 (en) | 2008-08-08 | 2010-09-28 | Oracle America, Inc. | Liquid-cooled rack with pre-cooler and post-cooler heat exchangers used for EMI shielding |
US20100032142A1 (en) | 2008-08-11 | 2010-02-11 | Sun Microsystems, Inc. | Liquid cooled rack with optimized air flow rate and liquid coolant flow |
US20100136895A1 (en) | 2008-08-19 | 2010-06-03 | Turner Logistics | Data center and methods for cooling thereof |
US20100094472A1 (en) | 2008-10-14 | 2010-04-15 | Woytowitz Peter J | Irrigation System With Soil Moisture Based Seasonal Watering Adjustment |
US20110265983A1 (en) | 2009-01-08 | 2011-11-03 | Leaneco Aps | Cooling apparatus and method |
US8184435B2 (en) | 2009-01-28 | 2012-05-22 | American Power Conversion Corporation | Hot aisle containment cooling system and method |
CN102334396A (en) | 2009-01-28 | 2012-01-25 | 美国能量变换公司 | Hot aisle containment cooling system and method |
US8146374B1 (en) | 2009-02-13 | 2012-04-03 | Source IT Energy, LLC | System and method for efficient utilization of energy generated by a utility plant |
US8297069B2 (en) | 2009-03-19 | 2012-10-30 | Vette Corporation | Modular scalable coolant distribution unit |
US8836258B2 (en) * | 2009-04-15 | 2014-09-16 | Mitsubishi Electric Corporation | Inverter device, motor driving device, refrigerating air conditioner, and power generation system |
US7903404B2 (en) | 2009-04-29 | 2011-03-08 | Hewlett-Packard Development Company, L.P. | Data centers |
US8427010B2 (en) * | 2009-05-29 | 2013-04-23 | General Electric Company | DC-to-AC power conversion system and method |
US20100300650A1 (en) | 2009-06-02 | 2010-12-02 | American Power Conversion Corporation | Container air handling unit and cooling method |
AU2010256688A1 (en) | 2009-06-02 | 2012-01-12 | Schneider Electric It Corporation | Container air handling unit and cooling method |
US8031468B2 (en) | 2009-06-03 | 2011-10-04 | American Power Conversion Corporation | Hot aisle containment cooling unit and method for cooling |
CN102461357A (en) | 2009-06-03 | 2012-05-16 | 美国能量变换公司 | Hot aisle containment cooling unit and method for cooling |
US8228046B2 (en) * | 2009-06-16 | 2012-07-24 | American Power Conversion Corporation | Apparatus and method for operating an uninterruptible power supply |
US20120103591A1 (en) | 2009-07-09 | 2012-05-03 | Hewlett-Packard Development Company, L.P. | Cooling apparatus |
US8208258B2 (en) | 2009-09-09 | 2012-06-26 | International Business Machines Corporation | System and method for facilitating parallel cooling of liquid-cooled electronics racks |
US8583290B2 (en) | 2009-09-09 | 2013-11-12 | International Business Machines Corporation | Cooling system and method minimizing power consumption in cooling liquid-cooled electronics racks |
US8253424B2 (en) * | 2009-09-11 | 2012-08-28 | Sma Solar Technology Ag | Topology surveying a series of capacitors |
US8120916B2 (en) | 2009-09-17 | 2012-02-21 | International Business Machines Corporation | Facilitating cooling of an electronics rack employing water vapor compression system |
US7907406B1 (en) | 2009-09-28 | 2011-03-15 | International Business Machines Corporation | System and method for standby mode cooling of a liquid-cooled electronics rack |
US20110141779A1 (en) * | 2009-12-11 | 2011-06-16 | Joseph Alan | Boost Multilevel Inverter System |
US8093746B2 (en) | 2009-12-16 | 2012-01-10 | General Electric Company | Control of four-leg transformerless uninterruptible power supply |
US8624561B1 (en) * | 2009-12-29 | 2014-01-07 | Solarbridge Technologies, Inc. | Power conversion having energy storage with dynamic reference |
US20110198057A1 (en) | 2010-02-12 | 2011-08-18 | Lange Torben B | Heat dissipation apparatus for data center |
US9425704B2 (en) * | 2010-03-03 | 2016-08-23 | Sma Solar Technology Ag | Power inverter with multi-fed on-board power supply for supplying a controller |
US20120319495A1 (en) * | 2010-03-03 | 2012-12-20 | Sma Solar Technology Ag | Power Inverter with Multi-Fed On-Board Power Supply |
US20110278934A1 (en) * | 2010-05-14 | 2011-11-17 | American Power Conversion Corporation | Digital control method for operating the ups systems in parallel |
US20120174612A1 (en) | 2010-05-21 | 2012-07-12 | Liebert Corporation | Computer Room Air Conditioner With Pre-Cooler |
US8189334B2 (en) | 2010-05-26 | 2012-05-29 | International Business Machines Corporation | Dehumidifying and re-humidifying cooling apparatus and method for an electronics rack |
US20110313576A1 (en) | 2010-06-17 | 2011-12-22 | Mark Randal Nicewonger | System and method for flowing fluids through electronic chassis modules |
US9793752B1 (en) | 2010-06-28 | 2017-10-17 | Amazon Technologies, Inc. | Reserve power system for data center |
US20120019230A1 (en) * | 2010-07-20 | 2012-01-26 | Vincotech Gmbh | Dc/dc converter circuit and method for controlling a dc/dc converter circuit |
US8472182B2 (en) | 2010-07-28 | 2013-06-25 | International Business Machines Corporation | Apparatus and method for facilitating dissipation of heat from a liquid-cooled electronics rack |
US20110141786A1 (en) * | 2010-09-29 | 2011-06-16 | General Electric Company | Dc-link voltage balancing system and method for multilevel converters |
US8783052B2 (en) | 2010-11-04 | 2014-07-22 | International Business Machines Corporation | Coolant-buffered, vapor-compression refrigeration with thermal storage and compressor cycling |
US8514575B2 (en) | 2010-11-16 | 2013-08-20 | International Business Machines Corporation | Multimodal cooling apparatus for an electronic system |
US8405977B2 (en) | 2010-12-30 | 2013-03-26 | Hon Hai Precision Industry Co., Ltd. | Container data center |
US20140009988A1 (en) | 2011-02-01 | 2014-01-09 | Power-One Italy S.P.A. | Modulation of Multi-Phase Inverter |
US8816533B2 (en) | 2011-02-16 | 2014-08-26 | Eaton Corporation | Uninterruptible power supply systems and methods using an isolated neutral reference |
US8730691B2 (en) * | 2011-05-11 | 2014-05-20 | Eaton Corporation | Power conversion apparatus and methods employing variable-level inverters |
US9203323B2 (en) * | 2011-09-22 | 2015-12-01 | Renewable Power Conversion, Inc. | Very high efficiency uninterruptible power supply |
US20130082636A1 (en) * | 2011-09-29 | 2013-04-04 | Daihen Corporation | Signal processor, filter, control circuit for power converter circuit, interconnection inverter system and pwm converter system |
US8760863B2 (en) | 2011-10-31 | 2014-06-24 | International Business Machines Corporation | Multi-rack assembly with shared cooling apparatus |
DE102012218873A1 (en) | 2011-10-31 | 2013-05-02 | International Business Machines Corporation | Multi-rack unit with shared cooling device |
US8797740B2 (en) | 2011-10-31 | 2014-08-05 | International Business Machines Corporation | Multi-rack assembly method with shared cooling unit |
US9362814B2 (en) * | 2011-12-23 | 2016-06-07 | North Carolina State University | Switched-capacitor DC-DC converter |
WO2014011706A1 (en) | 2012-07-09 | 2014-01-16 | Inertech Ip Llc | Transformerless multi-level medium-voltage uninterruptible power supply (ups) systems and methods |
US11539236B2 (en) * | 2012-07-09 | 2022-12-27 | Inertech Ip Llc | Multi-level uninterruptable power supply systems and methods |
US10873208B2 (en) * | 2012-07-09 | 2020-12-22 | Inertech Ip Llc | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) systems and methods |
US9985473B2 (en) * | 2012-07-09 | 2018-05-29 | Inertech Ip Llc | Transformerless multi-level medium-voltage uninterruptable power supply (UPS) system |
US20150188362A1 (en) | 2012-07-09 | 2015-07-02 | Inertech Ip Llc | Transformerless multi-level medium-voltage uninterruptable power supply (ups) system |
US8976556B2 (en) * | 2012-07-12 | 2015-03-10 | Mitsubishi Electric Research Laboratories, Inc. | Space vector modulation for multilevel inverters |
US9214874B2 (en) * | 2012-07-31 | 2015-12-15 | Yashomani Y. Kolhatkar | Intelligent level transition systems and methods for transformerless uninterruptible power supply |
EP2722978A2 (en) | 2012-10-22 | 2014-04-23 | Hamilton Sundstrand Corporation | System and method for common-mode elimination in a multi-level converter |
US20140152109A1 (en) | 2012-11-30 | 2014-06-05 | General Electric Company | Medium voltage uninterruptible power supply |
US20140334211A1 (en) * | 2013-05-07 | 2014-11-13 | University Of Central Florida Research Foundation, Inc. | Power inverter implementing phase skipping control |
US20140368043A1 (en) | 2013-06-14 | 2014-12-18 | General Electric Company | Systems and methods for grid interactive ups |
US20150021998A1 (en) * | 2013-07-18 | 2015-01-22 | Solantro Semiconductor Corp. | Stabilized power generation |
WO2015020868A1 (en) | 2013-08-05 | 2015-02-12 | Ragingwire Data Centers, Inc. | Electrical power management system and method |
US20150035358A1 (en) | 2013-08-05 | 2015-02-05 | Ragingwire Data Centers, Inc. | Electrical power management system and method |
US9774190B2 (en) * | 2013-09-09 | 2017-09-26 | Inertech Ip Llc | Multi-level medium voltage data center static synchronous compensator (DCSTATCOM) for active and reactive power control of data centers connected with grid energy storage and smart green distributed energy sources |
US11552474B2 (en) * | 2013-09-09 | 2023-01-10 | Inertech Ip Llc | Multi-level medium voltage data center static synchronous compensator (DCSTATCOM) for active and reactive power control of data centers connected with grid energy storage and smart green distributed energy sources |
US20150155712A1 (en) * | 2013-09-09 | 2015-06-04 | Inertech Ip Llc | Multi-level medium voltage data center static synchronous compensator (dcstatcom) for active and reactive power control of data centers connected with grid energy storage and smart green distributed energy sources |
US10951032B2 (en) * | 2013-09-09 | 2021-03-16 | Inertech Ip Llc | Multi-level medium voltage data center static synchronous compensator (DCSTATCOM) for active and reactive power control of data centers connected with grid energy storage and smart |
US9520800B2 (en) * | 2014-01-09 | 2016-12-13 | Rockwell Automation Technologies, Inc. | Multilevel converter systems and methods with reduced common mode voltage |
US20150280608A1 (en) * | 2014-03-26 | 2015-10-01 | Solaredge Technologies, Ltd | Multi-level inverter |
US20150370278A1 (en) * | 2014-06-20 | 2015-12-24 | Boe Technology Group Co., Ltd. | Maximum Power Point Tracking Method and Device, and Photovoltaic Power Generation System |
US10014713B1 (en) | 2014-07-31 | 2018-07-03 | Amazon Technologies, Inc. | Redundant secondary power support system |
US10033220B1 (en) | 2014-08-19 | 2018-07-24 | Amazon Technologies, Inc. | High-voltage energy storage system |
US10389272B2 (en) * | 2014-10-21 | 2019-08-20 | Inertech Ip Llc | Systems and methods for controlling multi-level diode-clamped inverters using Space Vector pulse width modulation (SVPWM) |
US9912251B2 (en) * | 2014-10-21 | 2018-03-06 | Inertech Ip Llc | Systems and methods for controlling multi-level diode-clamped inverters using space vector pulse width modulation (SVPWM) |
US20180294741A1 (en) * | 2014-10-21 | 2018-10-11 | Inertech Ip Llc | Systems and methods for controlling multi-level diode-clamped inverters using space vector pulse width modulation (svpwm) |
US10193380B2 (en) * | 2015-01-13 | 2019-01-29 | Inertech Ip Llc | Power sources and systems utilizing a common ultra-capacitor and battery hybrid energy storage system for both uninterruptible power supply and generator start-up functions |
US20160294188A1 (en) | 2015-03-30 | 2016-10-06 | Sonnenbatterie Gmbh | Energy supply system and conductor loop enclosure |
US20170028859A1 (en) * | 2015-07-30 | 2017-02-02 | Lsis Co., Ltd. | Apparatus for controlling charging/discharging of battery |
US10931190B2 (en) * | 2015-10-22 | 2021-02-23 | Inertech Ip Llc | Systems and methods for mitigating harmonics in electrical systems by using active and passive filtering techniques |
US20170117822A1 (en) * | 2015-10-23 | 2017-04-27 | Majid Pahlevaninezhad | Dynamic maximum efficiency tracker for pv micro-inverter |
US10673327B2 (en) * | 2016-12-22 | 2020-06-02 | Inertech Ip Llc | Systems and methods for isolated low voltage energy storage for data centers |
US11424677B2 (en) * | 2016-12-22 | 2022-08-23 | Inertech Ip Llc | Systems and methods for isolated low voltage energy storage for data centers |
US20180269782A1 (en) | 2016-12-22 | 2018-09-20 | Inertech Ip Llc | Systems and Methods for Isolated Low Voltage Energy Storage for Data Centers |
US20190260306A1 (en) * | 2017-01-11 | 2019-08-22 | Murata Manufacturing Co., Ltd. | Power converter |
Non-Patent Citations (9)
Title |
---|
Clark, Jeff, "Raising Data Center Power Density," 2013 [retrieved on Jan. 23, 2017] Retrieved from the Internet , 5 pgs. |
Doug Garday et al., :Air-Cooled High-Performance Data Centers: Case Studies and Best Methods, White Paper Intel Information Technology, Nov. 2006. |
HP Modular Cooling System User Guide, Hewlett-Packard Development Company, Feb. 2007. |
Kant et al., "Data Center Evolution A Tutorial on State of the Art, Issues, and Challenges", Computer Networks 53 ( 2009), 2939-2965. |
Liebert Xtreme Density—System Design Manual, 2009, . |
Miller, Troy, "Smart grid solutions for data centers (can you say "self-healing?"), " 2013 [retrieved on May 6, 2015] Retrieved from the Internet , 2 pgs. |
PCT International Search Report and Written Opinion for PCT/US2015/056785 dated Feb. 2, 2016. |
Reduced-Order Modeling of Multiscale Turbulent Convection: Application to Data Center Thermal Management, May 2006, . |
S&C Electric Co., "Solutions for Data Centers," 2015 [retrieved on Mar. 14, 2015] Retrieved from the Internet , 1 pg. |
Also Published As
Publication number | Publication date |
---|---|
US20210218269A1 (en) | 2021-07-15 |
WO2014011706A1 (en) | 2014-01-16 |
US9985473B2 (en) | 2018-05-29 |
US20150188362A1 (en) | 2015-07-02 |
US20230108992A1 (en) | 2023-04-06 |
US11539236B2 (en) | 2022-12-27 |
US10873208B2 (en) | 2020-12-22 |
US20190140476A1 (en) | 2019-05-09 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11923725B2 (en) | Transformerless multi-level medium-voltage uninterruptable power supply systems and methods | |
US11552474B2 (en) | Multi-level medium voltage data center static synchronous compensator (DCSTATCOM) for active and reactive power control of data centers connected with grid energy storage and smart green distributed energy sources | |
Vosoughi et al. | A new single-phase transformerless grid-connected inverter with boosting ability and common ground feature | |
Khomfoi et al. | Multilevel power converters | |
US20220014088A1 (en) | Systems and methods for mitigating harmonics in electrical systems by using active and passive filtering techniques | |
US8427010B2 (en) | DC-to-AC power conversion system and method | |
CA2732316A1 (en) | Power conversion apparatus | |
Sahoo et al. | High frequency link multi-winding power electronic transformer using modular multilevel converter for renewable energy integration | |
Shahbazi et al. | Power electronic converters in microgrid applications | |
Umuhoza et al. | A SiC-based power electronics interface for integrating a battery energy storage into the medium (13.8 kV) distribution system | |
EP3916975A2 (en) | Conversion device | |
Sahoo et al. | Modulation and control of a single-stage hvdc/ac solid state transformer using modular multilevel converter | |
Trintis et al. | Single stage grid converters for battery energy storage | |
Roncero-Clemente et al. | Interleaved single-phase quasi-Z-source inverter with special modulation technique | |
US20230068564A1 (en) | Conversion system and conversion device | |
Chellappan et al. | Power Topology Considerations for Solar String Inverters and Energy Storage Systems | |
da Silva et al. | Hybrid three-phase multilevel inverter based ON NPC cascaded to half-bridge cells | |
Sandeep et al. | Switched-capacitor-based three-phase five-level inverter topology with reduced components | |
Jalakas et al. | Electric vehicle fast charger high voltage input multiport converter topology analysis | |
Cheng et al. | The topology analysis and compare of high-frequency power electronic transformer | |
de Oliveira Pacheco et al. | Bidirectional modular multilevel PFC rectifier based on cascading full-bridge and interleaving technique suitable for SST applications | |
WO2023219595A1 (en) | Transformerless 3-phase, 3-level t-type npc unfolding inverter with 3 hf switches on dc side | |
Neti et al. | Common Ground Single-Phase Single-Stage Transformerless Inverter Five Levels Using Reduced Components and Switched Capacitor Cell | |
CN117559821A (en) | Five-level AC/DC converter suitable for medium-voltage solid-state transformer and control method thereof | |
REDDY et al. | A NEW SWITCHED-CAPACITOR MULTILEVEL INVERTER FOR HIGH FREQUENCY AC POWER DISTRIBUTION SYSTEMS |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: INERTECH IP LLC, CONNECTICUT Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MONDAL, SUBRATA K.;REEL/FRAME:062042/0492 Effective date: 20120710 |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO SMALL (ORIGINAL EVENT CODE: SMAL); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT RECEIVED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |